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NATIONAL ADVISORY COMMITTEE 
FOR AERONAUTICS 



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TECHNICAL NOTE 

No. 1247 



THE PREPARATION AND PHYSICAL PROPERTIES OF SEVERAL 

ALIPHATIC HYDROCARBONS AND INTERMEDIATES 

By Frank L. Howard, Thomas W. Mears, A. Fookson, 

Philip Pomerantz, and Donald B. Brooks 

National Bureau of Standards 



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Washington 
May 1947 



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TECH LIBRARY KAFB.NM 

NACA TN No. 12kj 

t 

TABLE OF CONSENTS 



Page 

SUMMARY 1 

INTRODUCTION 1 

APPARATUS . . ' '■ 2 

Reaction Vessels . .............. 2 

Hydrogenation Equipment 2 

Sti lls 3 

DETERMINATION OF PHYSICAL PROPERTIES k 

PREPARATION OF MATERIALS 5 

Preparation of G-rignard Reagents 5 

n-Pentane 6 

2-MethyTbutane (Isopentane) •*•. • .• 7 

2, 2-Dimethylpropane (Neopentane) ...... ... 7 

3-Methylpentane ......... . 9 

2, 2-Dimethyrbutane (Neohexane) 9 

2-Methylpentane ................ 10 

Investigation of Butene Alkylate ..... 10 

2,3-DimethyTbutane 10 

2,J4-Dimethylpentane 11 

2, 3-Dimethylpentane from Isooctane ..... 11 

2,2,3-Trimethyrbutane (Triptane) 11 

2-Methyl-3-Ethylpentane 13 

2,3,3-Trimethylpentane - 13 

2,2,3-Trimethylpentane and 2,3,4-TrImethylpentane ....... it 

2,2,5-Trimethylhexane Ik 

2,3,5-Trimethylhexane . . , i . c 14 

2,2,lt--Trimethylhexane . 17 

2,2-Dimethyl-3-Ethylpentane 18 

# 2,l4--Dimethyl-3-Ethylpentane 19 

2,2,3,3-Tetramethylpentane (Tetrane) . 20 

2, 2, 3, 4-Tetramethylpentane and 2,3,3,4-Tetramethylpentane ... 22 

Dimethyl -Zinc Synthesis of Three Tetramethylpentanes 2k 

2,2,3,3-Tetramethylpentane 2k 

2,2,3,11- and 2,3,3,li-Tetramethylpentanes 25 

# 2,l|--Dimethyl-3-Isopropylpentane (Trlisopropylmethane) 27 

Pent ame thy lpentanes 29 

2,2,5,5-Tetramethylhexane and 2,2,4,5-Tetramethylhezane .... 38 

^2,2,3,3-Tetramethylhezane kl 

3>3A^"Tetraiaethylhezane kl 

2,3-Dimethyl-l-Butene and 2, 3-Dimethyl-2-Butene k2 

3-Methyl-2-Pentenes (cis and trans) kk 

Investigation of Diisohutylene kk 

Investigation of Hot-Acid Polymer (Shell Oil Company) k6 

REFERENCES JU-8 

TABLES .' . . , . 52 



NATIONAL ADVISORY COMMITTEE FOR AERONAT3TICS 



TECHNICAL NOTE- NO. 12^7 



THE PREPARATION AND PHYSICAL PROPERTIES OP SEVERAL 

ALIPHATIC HYDROCARBONS AND INTERMEDIATES 

^By Frank L. Howard, Thomas W. Mears, A. Fookson, 
Philip Pomerantz, and Donald B. Brooks 

SUMMARY 



, In the course of an- investigation of the knock ratings of aliphatic 
hydrocarbons, pure paraffins and olefins were prepared in quantities 
sufficient for engine tests. This report describes the methods of prep- 
aration and purification of three pentanes, four hexanes, three heptanes, 
four octanes, eight nonanes, seven decanes, four hexenes, five octenes, 
six nonenes, six decenes, and a number of alcohols, ketones, esters, and 
alkyl halides. Most of these compounds were highly purified. Physical 
oonstants measured included freezing point, "boiling point and its varia- 
tion with pressure, refractive index and density, and their variations 
with temperature. 



INTRODUCTION 

In 193^ the Automotive Section of the National. Bureau of. Standards 
undertook an investigation of the. impurities present in the certified 
lscoctane (2,2,^~trimethylpentane) used as a primary standard in the 
knock rating of fuels. In the course of this .work, about a score of 
paraffin hydrocarbons were isolated and thqir physical properties and 
knock ratings were determined. (See reference 1.) The information ob- 
tained in this work indicated that some of the higher paraffin hydro- 
carbons should he decidedly superior to isooctane in knock rating. 

The results of this work led to a research- project that was initi- 
ated with the objective of preparing, in quantities sufficient for engine 
tests, the paraffin hydrocarbons likely to he of interest as components 
of combat aviation fuel. This project was begun in 1937 under Joint 
sponsorship of the National Advisory Committee for Aeronautics, the Army 
Air Forces, and the Navy Bureau- of Aeronautics and has been actively 
prosecuted since that time. The results of portions of this investigation 



2 NACA TN No . 12^7 

completed prior to 19**0 hare been presented in references 2 to 5, and- 
the syntheses and physical properties of a number of additional aliphatic 
hydrocarbons are described in the present paper. 

Since the objective of this work was the preparation of pure hydro- 
carbons for engine testing to determine knock rating, it was generally 
necessary to subordinate other considerations to this purpose. In many 
cases, it was therefore not possible to make detailed studies of the re- 
actions or to determine properties of some of the new or little-known 
intermediates . 

Acknowledgments are due the following people for aid and advice on 
various phases of this work: Dr. Cecil E. Boord, Ohio State University, 
Dr. George Calingaert and Dr. Harold A. Soroos, Ethyl Corporation Re- 
search Laboratories, Dr. Nathan L. Drake, University of Maryland, Dr. 
Merrill R. Fenske and Dr. Frank C. Vhitmore, Pennsylvania State College, 
and Dr. Frederick D. Rossini, National Bureau of Standards. 

APPARATUS 
Reaction "Vessels 



Small-scale exploratory reactions were generally carried out in 5- 
liter glass flasks. In some cases, where an unusually low yield of 
final product was expected, 12-liter flasks were used. The use of these 
larger flasks was discontinued in 19^, and reactions of this size were 
then conducted in llj--liter brass double-walled vessels. For synthesis 
on a larger scale, two copper reactors were used initially. Each of 
these reactors had a capacity of 60 liters and was double walled. Water 
at any desired temperature between 5° and 75° C could he circulated in 
the space between the walls to control the temperature of the reaction. 
The reactors were equipped with multiple -paddle stirrers (60 to 200 rpm), 
reflux condensers (multiple copper tube), separatory funnels for addi- 
tion of reactants, and draw-off valves for removal of products. These 
reactors were used until early in 19^, when two 50-gallon kettles (one 
glass lined, one stainless steel) were put into service. The copper 
reactors were then used as distillation receivers in conjunction with 
the large kettles. The large kettles were standard commercial items 
and were installed so that any temperature "between 5° s*id 150° C could 
"be maintained in the jackets. 

Hydrogenation Equipment 

Hydrogenation reactions were accomplished in high-pressure hydro- 
genators, designed after those described by Adkins in reference 6. 



MCA TN No. 12V7 



Three sizes were used, with capacities of 1, 3, and 20 liters. The cat- 
alyst used vas a coxmnercial nickel-on-kieselguhr preparation, which 
proved to "be economical and efficient. No difficulty was encountered in 
hydrogenating any of the materials, provided they were halogen- free . 
Most, of the hydrogenation reactions took place at temperatures "below 
l60° C and pressures "below 2000 pounds per square inch. 

Stills 

For convenience, the various stills used in this work are desig- 
nated in the text "by numbers. The salient features of these stills are 
given in ta"ble 1. Some of these columns are no longer in use, having 
"been supplanted "by others of later designs. Operations formerly per- 
formed in Columns 1 and 2 were later carried out in 19 and 20, and Col- 
umns 8 and 9 were replaced "by 17 and 18. Column 10 was abandoned in 
I9U2, when Column 11 was put into operation. Columns 3 to 7 were re- 
placed "by 21 to 27 late in 19^5. 

Still 1 .- This still is of the. total-reflux, intermittent take-off 
type, and has "been previously described in reference 5. The reflux rate 
was approximately 1500 ml per hour in most cases, the take-off rate "be- 
ing governed "by the composition of the charge and the purity desired in 
the product. Samples of 78 ml each were removed" automatically at prede- 
termined intervals varying from 0.5 to 2k hours. The efficiency is ap- 
proximately ninety to ninety-five theoretical plates, and the' hold-up is 
260 ml. • 

Still 2 .- The column of this' still consists of 150 actual plates, 
following the design "by J. H. Brunn. (See reference 7.) The volume of 
each fraction removed was 65 ml. Reflux rate was a"bout 800 ml per hour. 
This still has also "been described in reference 5* Th© mechanisms of 
operation and sample removal are the same as for Still 1. ' In" "both 
Stills 1 and 2 the head temperature was followed' during the 'day "by means 
of a platinum resistance thermometer, and the timing operations were 
scheduled so that samples were .removed when this temperature (corrected 
to 760 mm Hg) "became reasonably constant (generally to within a change 
of less than .005° C per hr) . 

Stills 3 to 9 .- Small stills patterned after those described "by 
Whitmore and. Lux (reference 8) . were used to remove other from reaction 
mixtures, for purification of intermediates, for preliminary purifica- 
tion of final products, and for fractionation of small charges. These 
stills are designated as, 3 to 9 in ta"ble 1. 

Still 10 .- Prior to the construction of other large-capacity stills, 
Still 10 was used for .preliminary fractionation of commercial synthetic 
crudes. The pot was part Qf a domestic ho't-water tank, the column a 



k NACA TN No. 12^7 

length of 2-inch pipe. The take-off was governed "by a l/8-inch needle 
valve . 

Still 11 .- In order to have a higher-oapacity, higher-efficiency 
still than 10, Still 11 was constructed. The entire still is made of 
monel metal. The reflux rate Is about h liters per hour, as measured by 
gain in temperaturo of the condenser water; The take-off rato is gov- 
erned "by a commercial l/8-lnch solenoid valve, operated "by an automatic 
timing device. The efficiency of the still is about sixty-five theoret- 
ical plates under operating conditions ( 3 .5 to h .5 liters per hr reflux) . 
Safety devices include overflow tanks for the salvaging of material dis- 
tilled through the condenser if the water is accidentally cut off, a 
product overflew tank for retaining material which may he delivered "be- 
cause of faulty operation of the solenoid valve, and a-pot-tezuperature- 
limit control. All openings to the still are vented to the outside of 
the. building. 

' Stills 12 to l6.- These columns were oonstructod for analysis of 
commercial crudes, purification of large quantities of material, and 
isolation of hydrocarbons from commercial mixtures. These were put into 
operation in 19*K3, and later (19^5) Column 11 was lengthened by k feet 
and added to the group. The take-off on all these stills is governed by 
a timer and small solenoid valves. Condensers In the larger columns are 
of the multiple cold-finger type. The columns are heated by resistance 
wire controlled by variable transformers. Temperatures are measured by 
copper-constantan thermocouples. Safety devices include overflow tanks, 
automatic pot-temperature-limlt control, forood ventilation, automatic 
carbon-dioxide fire control (controlled by thermal-plugs), and automatic 
warning if the atmosphere approaches a combustible mixture. The pots of 
Stills 12 to 16 are made of mild steel'. The columns of 12 and 13 are 
made of galvanized pipe, and the columns of Ik and 15 are made of stain- 
less steel. Condensers are of copper, brass, or monel metal. 

KETERMINATIOIf OF PHYSICAL PROPERTIES 



From the plots of refractive indices, boiling points, or freezing 
points of fractions with respect to volume of distillate, those fractions 
containing the best material were selected and used for the determination 
of physical constants. 

The methods used for the determination of physical constants have 
been described in referenoe k. The freezing-point apparatus was modified 
In December 19kk, so that additional control of the rate of cooling could 
be obtained. This was done by installing a pumping system on the evacu- 
ated chamber surrounding the sample, so that the rate of cooling oould be 
governed by the pressure in the evacuated chamber. This modification of 



NACA TIT JTo . 12^7 5 

the equipment has "been adequately described "by Mair (reference 9) . 
Table 2 lists the measured physical properties of the compounds de- 
scribed herein. 

The freezing-point data on 2,2,5,5-tetramethylhexane are considered 
representative, and are illustrated, in figure 1. Boiling-point data on 
four compounds are shown in figure 2. These figures are presented as 
typical examples of measured physical properties. Eefractive indices 
were measured on an Abbe type (Talentlne) refraetomster until 19^3 when 
a Bausch and Lomb precision-oil r6fraotometer (also Abbe type) was put 
into use. An estimate of the purity of the Individual compounds may be 
made from the data listed in table 2 under the heading £T:20 to 80 per- 
cent, vhich Indicates the number of degrees difference between the tem- 
perature at which 20 percent of the material had distilled and the tem- 
perature at which 30 percent had distilled. The presence of peroxides 
In the olefin samples tended to make this difference extraordinarily 
large . 



PKEPAP.ATI0N OF MATERIALS 
Grignard Reagents 

The preparation of Grignard. reagents in large quantities (up to 
339 moles) has been found to be subject to the' same limitations as the 
preparation of small amounts, except that the yields, in general, are 
slightly larger. The methods used in typical runs of representative 
members of the aliphatic series aro given as follows, and are not re- 
peated in the discussion of the various syntheses. Decomposition of 
reaction complexes formed by the action of Grignard reagents on various 
compounds followed the classical methods and need not be repeated. 

Methylmagnesium bromide .- To the reactor was added 100 gram atoms''' 
(2 A3 kg) of magnesium turnings and enough ether to cover the magnesium. 
A small amount of methyl bromide was added . If reaction did not start 
Immediately, a little methyl iodide (or previously prepared Grignard 
reagent) was added. After reaction had been initiated the stirrer was 
started, and methyl bromide from a cylinder supported from a steelyard 
was allowed to flow through a coll of copper tubing surrounded by a dry- 
ice bath where it condensed and dropped Into the reaction mixture . Flow 
was regulated by a small needle valve. After the reaction was well 
started, cooling water was admitted to the ■ jacket, and an excess of 
methyl bromide was added as fast as it would rsact. During the addition 
of methyl bromide, ether was added In 2 -liter portions until the total 
ether added was 20 liters ( 200 ml per gram atom of magnesium) . The 
amount of methyl bromide added was determined by the loss of weight of 
the cylinder, and it was found that practically no methyl bromide was 
lost during the operation. After addition of methyl bromide was 



6 MCA TN No . 1247 



complete, the reaction mixture was warmed for 2 to 3 hours. If the mix- 
ture contained sludge or pieces of unreacted magnesium, it was allowed to 
stand until the sludge had settled, and then the clear solution was si- 
phoned off. The sludge was next washed with dry ether and allowed to 
settle, then the siphoning procedure was repeated. If the amoung of 
sludge was small, this last operation was carried out advantageously in 
a separatory funnel, in which the sludge could he drawn off easily. 

The yields varied from 88 to 95 percent, "based on magnesium, as de- 
termined "by titration. Similar yields were realized when ethyl magnesium 
chloride was prepared, hut in this case slower addition of halide was 
necessary in order to avoid the formation of appreciable amounts of 
sludge . 

Isopropylmagnesium chl oride.- Magnesium turnings (1.5 kg, 6*3 gram 
atoms) and 5 liters of ether wore placed in the reactor, and reaction 
was started "by the addition of a small amount of lsopropyl chloride • 
After the reaction was initiated, the stirrer was started and 1 liter 
of lsopropyl chloride in 2 liters of ether was added slowly. After this 
first charge of chloride was complete, 5 liters of ether and the rest of 
the magnesium (1.5 kg, 63 gram atoms) were added, and cooling water was 
circulated through the jacket. Then the rest of the chloride and ether 
was added in the ratio of 1 liter of chloride for 2.0 to 2.5 liters of 
other, until a total of 125 moles of chloride and 37.5 liters of ether 
had "been used. This addition was carried out as fast as possible, still 
keeping the reflux from the condenser dropwise and not in a steady stream. 
About 35 hours were required for a 125-mole run. After removal of the 
clear solution from the sludge, the yield, calculated from titration data, 
amounted to 90 to 93 percent of the theoretical quantity'. 

t-Butylmagnesium chloride .- This preparation was carried out in es- 
sentially the same manner as descrihed for the preparation of isopropyl- 
magnesium chloride, except that the addition of chloride was necessarily 
slower In order to retard formation of hexamethylethane, isohutylene, and 
diisohutylene. A 70-mole run required approximately 35 hours. The lat- 
ter half of the chloride added was more dilute than the first half (ref- 
erence 10) and the rate of addition was slowed up progressively as the re- 
action neared completion. The Jacket of the reactor was not cooled so 
much in this preparation as with the less highly "branched halidee. The 
tendency of t -"butyl chloride to form sludge is much greater than that of 
the simpler halldes, although many runs were made in which practically no 
sludge was observed. The yields varied from 80 to 92 percent. 



n-Pentane 

One gallon of commercial n-pentane was fractionated in Still 1. 
From this distillation there was obtained 1792 ml of material, the 



NACA TN No . 12U7 7 

fractions of which had e refractive index nj^° of 1-357^ to I.3575. A 
"■best", sample was selected for determination of physical constants. 

2-Methylbutane (Isopentane) 

One gallon of commercial isopentane was fractionated In Still 1. 
There was obtained 2200 ml of material, np 20 = 1.3535 to 1.3536, which 
was collected while the head temperature of the column was 27. 87 to 
27 .88° C . Later a total of kj liters of high-purity material was pre- 
pared from the same source "by fractionation in Still 11. 

2,2-Dimethylpropane (Ueopentane) 

In 1933, Whitmore and Fleming (reference 11) described the prepara- 
tion of neopentane "by reaction "between methytoagnesium chloride and 
t-butyl chloride in toluene at 14-5° to 50° C. Yields of k-2 to 50 percent 
were reported. ' Iin the present work, a method is described whereby some- 
what larger .yields of purer product were obtained. 

In this work, neopentane was prepared "by action of dimethyl zinc on 
t-butyl chloride in toluene at 5° C. The advantage of causing reaction 
at this temperature, rather than the often used higher temperature (35° 
to 50° C) .for reactions of this type has "been previously demonstrated. 
(See reference 2.) Dimethyl ' zinc was -prepared in the mariner described 
in reference 2; however, certain Improvements in the technique of han- 
dling this material have been made. 

A 5-liter, single-neck flask, which was used for dimethyl- zinc prep- 
. aration, was placed In : an oil bath and fitted- with a U00 -millimeter 
reflux condenser ; . To the top of the condenser was attached a bridge of 
10-millimeter glass tubing which led. to the top of a similar reflux con- 
denser attached to a 5-liter, threB-neck flask. This latter flask, Into 
which dimethyl zinc was distilled, was situated in a cold-water bath and 
was provided with a separatory funnel (500 ml) and a stirrer. A side 
arm on the bridge provided for the ' introduction of Inert gas (carbon 
dioxide) . ... 

The zinc-copper couple from 960 grams of zinc dust and 120 grams of 
cupric oxide was placed in' the one -neck flask, and 1100 grams (7.75 
moles) of methyl iodide added. The temperature of the oil bath was 
raised, to about h^° C, and a slow stream of carbon dioxide was passed in 
the side arm of the bridge and out through the separatory funnel into a 
venting tube made of 25-millime'ter glass tubing. Reaction between 
methyl iodide and. the couple was complete after 10 hours, provided that 
the couple was sufficiently active. When reaction had ceased, .as shown 
by the cessation of refltix, the carbon-dioxide flow was stopped, 500 ml 



8 NACA IN No . 121*7 



of toluene was added to the three-neck flask, and the top of the separa- 
tory funnel' was fitted with a tee tube . The reflux condenser on the one- 
neck flask was heated with steam, and the temperature of the oil hath 
was gradually raised over a period of 2 hours to about l8o° C . This 
caused the methylzinc iodide in the flask to decompose into dimethyl zinc 
'and zinc iodide. The dimethyl zinc distilled across the "bridge into the 
toluene in the three -neck flask. Carbon dioxide was allowed to flow 
through the top of the tee while distillation of dimethyl zinc was in 
progress. 

After distillation of dimethyl zinc was complete, the single-neck 
flask waB allowed to cool and the side arm on the bridge connected to a 
gas-purification train comprising, in the order named, a wash "bottle con- 
taining water, two "bottles containing 85 -percent sulfuric acid, an empty 
"bottle, a "bottle containing ^0-percent potassium hydroxide, a calcium- 
chloride drying tower, and a 100- "by 1.5-centimeter tube fj lied with 
silica gel. After passing through. this train, the gas was led into a 
condensing Bystem comprising a copper coll condenser at -10° C, a re- 
ceiver at -78 C, and finally a trap at -78 C. 

The flask containing toluene and dimethyl zinc was cooled to 5 C, 
and 525 ml (about h.Q moles) of t-butyl chloride in 750 ml of dry toluene 
was added during 5 hours. During the addition of- chloride, methene was 
evolved by the reaction. After the addition of chloride was complete, 
the reaction mixture was allowed to stand 15 hours. Then the bath tem- 
perature was raised gradually to 50° 0, during which time more gas was 
given off which was not affected by the sulfuric acid and which did not 
condense in the -78 a C trap . ... 

"Water was then added to the reaction mixture .through the separatory 
funnel. It was necessary to exercise considerable care in this opera- 
tion, since- a violent evolution of neopentane took place at this point. 
This, gas was condensed in the -10° C condenser, and solidified in the 
receiver. There was no discoloration of the sulfuric acid. After, about 
200 ml of water had been added and the evolution of gas had subsided, 
the apparatus was swept out with nitrogen. 

The- resulting neopentane was transferred to a glass tube and Bealed. 
The yield amounted to 164.5 grams, which is 59 percent of that theoreti- 
cally possible, based on one half the amount of methyl iodide used (2 
moles of methyl iodide give 1 mole of dimethyl zinc). The residue from 
the dimethyl zinc, which contained zinc Iodide, was used to prepare addi- 
tional methyl iodide by the method described In reference 12. 

In assembling the apparatus, corkB, rather than rubber stoppers, 
were used exclusively and after assembly they were coated with shellac . 
In one preliminary experiment, in which rubber stoppers were used, the 
product was contaminated with a material which had the odor of methyl 



NACA TN No . 12^7 9 

mercaptan. Where rubber tubing was necessary in making connections to 
the side arm on the' "bridge," arrangeiiient was made so that a minimum of 
rubber surface was exposed. 

The yield reported on the first run was verified later when nine 
additional runs of this preparation were- made, in which an average yield 
of 65.6, percent was. obtained, m two of these runs, the couple was less 
active than in the other preparations, and the product was contaminated 
with methyl iodide. The presence of methyl iodide was characterized "by 
a pink color which developed in the product after a few days. The yield 
obtained in one run was low because a stoppage developed in the purifica- 
tion train, and some material was lost through a" loosened connection. 

Freezing-point measurements made on the material from three experi- 
ments gave -the values -I0.61 , -l6.6l°, and -16.60 C, respectively. 
These data may "be compared with the value -16.63 ±0.10° C, calculated 
for the freezing point of 100 -percent-pure neopentane by Aston and 
Messerly'. "(See, reference 13 . ) 

3-Methylpentane ■ 

From 75*2 moles of ethyl magnesium chloride and 37 moles of ethyl 
acetate there was prepared 3660 ml of 3-methyl-3-pentanol, which was 
purified "by distillation in Column 7 ("b.p< 120° to 124° C at 76O mm). 
Dehydration of this carbinol "by refluxing with 0.2-percent 3. -naphthalene 
sulfonic acid .yielded a mixture of . alkenes which "boiled 65 to 71° C at 
758 millimeters. This dehydration would "be expected to yield chiefly 3- 
methyl-2-pentane, with a smaller amount of 2-ethyl-l-butene . No attempt 
was 'made to separate the two" olefins. since both compounds yield the same 
alkane" when, hydrogenated . . Hydrogenatibn of this mixture gave crude 
alkane which was filtered through silica gel and distilled in. Column k 
to. yield 1980 ml of material which boiled" 64.5° to 65 .5° C (uncorrected). 
Redistillation in Column 1 gave- 1^20 ml of hydrocarbon made up of frac- 
tions' removed while the head temperature was 63.319 to 63. 322° C (76I.I 
mm Jig) and for which . n-jf° =. 1.376k to I.3765. . ;' 

' . ■ 2,2-Dimethylbutane (Neohexane) . . . 

The synthesis of neohexane has been reported previously: in refer- 
ence k. Since then commercial neohexane has become available. Several 
charges of this material were fractionated in Stills 1 and 2 . ■ From each 
run, only the latter half "of the distillate consisted of material having 
this properties of neohexane . The forerun contained -an -impurity of 
higher refractive index and' slightly lower "boiling point. No extensive 
investigation was made of this forerun, "but the most likely impurity was 
cyclopentane . This fact was later substantiated "by the manufacturer. 



10 



NACA TN No. 12U7 



A total of. 38 liters of 'purified neohexane .was propared "by fractionation 
of 75 liters' of the commercial crude mixture in Still 11. 



2 -Me thy lpent arte 

About 75 liters of commercial crude neohexane was fractionated, to 
prepare 38 liters of 2, 2-dimethylbutane . From the distillations of this 
material, there was obtained 3320 ml of residue, which, was fractionated 
in Column 2 into k6 fractions : 



Fraction 


Boiling range 
(Head temperature) 

(°c) 


Volume 
(ml) 


Refractive index, np 20 


1 to 22 
23 to kk 
k$ to k6 


58.8 to 60..2 

60.2 to 60. k 

60. k 


1500 

1500 

litO 


I.37W to 1.3717 
1.3715 to 1.3717 
1.3717 to I.37IA 



Fractions 35 to 37 were combined, filtered through silica gel, and used 
in the determinations of physical properties of 2-methylpentane . 



Investigation of Butene Alkylate 

Seventy-five liters of Butene Alkylate was fractionated in Still 10. 
The head temperature was measured by means of a recording thermometer of 
the gas-expansion type. The reflux ratio was maintained' at about 100 to 
1. Fractions of not more than 3.87 liters each were collected, the vol- 
ume of the fraction depending on the time -temperature curv* . After 
measurement of refractive indices,' .like fractions from different runs 
were combined and refractionated in Still 2. Fractionation of the low- 
est 'boiling portion from Still 10 was carried out first, then the second 
lowest "boiling was added to. the residue and fractionated, and so on. 
The refractive index of each fraction was measured, and a plot of refrac- 
tive index versus fraction number was made. Samples represented by sin- 
gle plateaus were combined and redistilled in Column 1 or 2. Several 
hydrocarbons were isolated thereby, and are listed in table 3» 

2 , 3-Dimethylbutane ♦ - The 2,3-dimethylbutane from Butene Alkylate 
( 2213 ml) was added to 1255 ml of 2,3-dimethylbutane of approximately 
the same purity from another source. The combined material was washed 
with sulfuric acid, water, sodium-carbonate solution, and again with 
water. • After it was dried and filtered through silica gel, it was frac- 
tionated in Still 2, and gave 2300 ml of material for which 
ni, 20 ■> I.37WJ to 1.37^9. 



NACA TH No . 12^7 11 

2 , U-Dime thylpentane . - The' 2, It-dimethyl pentane from Butene Alkylate 
(26l0 ml) was refract ionated in Still 2. The fractions for which 

nD ao = I.3816 to I.3817 were reserved as the best portion, and amounted 
to 985 ml. 

2,3-Dimethylpentane from Isooctane 

Seventy-five liters of isooctane (a commercial mixture of "branched 
chain hydrocarbons) was fractionated in Still 10 in the manner described 
in the preceding section. Fractions which distilled "between 85 and 
95° C (n© 20 - 1.3886 to 1.391*0 were combined (28,051 ml) and refraction- 
ated in Still 11. Prom this distillation there was obtained 7165 ml of 
hydrocarbon which boiled 89 .7° to 90.0° C (n D ao = l;39l8 to 1.3921) which 
was refractionated in Still 2. The purified 2,3-dimethylpentane thereby 
obtained amounted to lj-790 ml after filtration through silica gel. The 
refractive index range n^ 20 ; of various fractions was l«3919i "to 1.39l9e* 

2,2,3-Trimethyrbutane (Triptane) 

. The synthesis of triptane involved two reactions: (a) the prepara- 
tion of 2-chloro- 2,3-dimethylbutane, arid (b) the reaction of this chlo- 
ride with, dimethyl zinc. 

i 2-Chloro- 2,3-dimethylbutane .- The apparatus used was, similar to 
that, described in. reference 2 for. the' preparation of ij--chloro- 2,2 ,k- 
trimethylpentane . it was modified 'so that rubber stoppers were replaced 
with grou nd -glass connections. The alkene used was a mixture of 2,3- 
dimethyl-1-butens and 2,3-dimethyl-2-bute.ne,. which was formed by dehydra- 
tion of pinac.plyL alcohol' (3,3r-dimethyl-2:;butanol).. (See reference 5.) 
The original-, alkene mixture contained £. small amount, of 3,3-dimethyl-l- 
butene, in. addition to the hexenes, but this hydrocarbon was removed for 
use.; in .another, synthesis.. k .."'■' 

In 2 hours, 1500 ml of the alkene mixture, along with excesB hydro- 
gen-chloride, was passed through two chambers kept in a bath .at -78" C. 
Occasionally it was riepessary to remove the. baths in. order to allow the 
solidified chloride to melt. and. pass on through the apparatus. The prod- 
uct, was, washed with water, with 5.-percent sodium-bicarbonate solution, 
again with water, and dried with two successive portions of fresh anhy- 
drous potassium carbonate. Distillation. of the resulting material in 
Column 3 gave, after a forerun of unchanged alkene. 675 grams of 2-chloro- 
2,3-dimethylbutane (b.p. 69 to 70° C at I90 mm Hg) . 

Synthesis of triptane .- With apparatus like that used in the prepa- 
ration of neopentane, dimethyl zinc was prepared from 1100 grams (7.75 



12 



NACA TN No. 12^7 



moles) of methyl iodide and distilled into a 5-liter flask containing 
500 ml of toluene. The flask was surrounded "by ice, and the chloride 
600 grams, 5 moles) in 1000 ml of toluene was added during h hours. The 
mixture was allowed to stand for 16 hours, and was then treated with 
water and with dilute hydrochloric acid. The reaction product, 2060 ml, 
was fractionated in Column 5 to give a small amount of methyl iodide, 
some olefinic material, presumably dime thy rbutenes formed "by dehydro- 
chlorination of the alkyl chloride, and 297 ml of crude triptane "boiling 
at 78° to 83 C, with nj) 20 = I.3932. Two passages through silica gel 
gave a product of the following properties, compared with those of high- 
purity material: 



Property 


Present 
preparation 


High-purity 

material 
(reference 5) 


Refractive index, n D 

Density, d 4 2 ° 

Freezing point, °C 
Boiling point, °C 


I.3897 

O.6896 

-26.1 
81.0 (Cottrell) 


1.389^7 

.69000 

-25 .059 
80.879 



The yield of crude triptane amounted to 51 percent of the theoretical. 

In subsequent experiments it was found that a large excess of alkyl 
chloride offered no addvantage, a 2- to 3-percent excess giving a compara- 
ble yield. The excess chloride was found to "be easily removed hy "boiling 
the crude mixture with a 5- percent solution of potassium hydroxide in 
alcohol. 



In each of several experiments, the yield amounted to k6 to 52 per- 
cent of crude triptane. The time allowed for addition of chloride was 
varied from 3 to 8 hours, and the temperature of reaction from 0° to 30° C 
without any appreciable change in yield. In one experiment, in which is'o- 
octane (2,2,l|--trimethylpentane) was used as a solvent, the yield was k8 
percent. 

. Under the conditions of hydrochlorination, 2,3-dimethyl-l-"butene was 
found to add hydrogen chloride more easily than 2,3-dimethyl-2-"butene. 
The unreacted alkene which was recovered when a mixture of the two was 
hydrochlorinated was found to "be practically pure 2,3-dimethyl-2-"butene. 
Very clight decomposition of 2-chloro- 2,3-dimethyl"butane takes place 
when it is "boiled at atmospheric pressure. 



MCA. TN Ho . 12^7 ■ 13- 



2-M6thyl-3-Bthylpentane . 

This octane vas prepared "by hydrogenation of the olefins" wh'ich re-' 
suited from the dehydration of 2-methyl-3-ethyl-3-pentanol. The carbinol 
was prepared "by the action of ethylmagnesium chloride on isobutyl iso- 
butyrate . 

To a solution containing 90 moles of ethylmagnesium chloride in 20 
liters of ether was added 6335 grams (kk moles) of isobutyl isobutyrate 
in 10 »5 liters of ether. The product vas dried with sodium carbonate and 
distilled in Column 6. There was obtained 5680 ml of 2-methyl-3-ethyl- 
3-pentanol (55° to 57° C at 1*8 ma. Eg) . Dehydration was effected "by re- 
flusing the carbinol with 0.2 percent "by weight of p-naphthalene sulfonic 
acid, which gave 5235 ml of crude alkene mixture, "boiling at llfc° to 
119° C. Since dehydration of 2-methyl-3-ethyl-3-pentanol should yield 
two alkenes: namely, 2-metbyl-3-ethyl-2-pentene (b.p. about 117° C) and 
lj--methyl-3-ethyl-2-pentene (-"b.p. about il6° C), "both of which yield the 
same alkane on hydrogenation, no attempt was made to separate the two. 
The alkene mixture was driod with calcium chloride and distilled from so- 
dium. A portion of the distillate (Ij-721 ml) was hydrogenated to the 
alkane, which, after two distillations from sodium and filtration through 
silica gel, amounted to U050 ml. The compound was finally fractionated 
in Still 1, yielding 3300 ml of material, .which had a refractive index 
constant within 0,0001. 



2,3,3 -Tr ime thylpentane 

This hydrocarbon resulted from the reaction "between isopropyl magne - 
sium chlorido and-t-anyl chloride* 

To 90 .5 moles of ieopropylmagnesium chloride in 30*9 liters of ether 
solution was added 9600 grams (90 moles) of t-amyl chloride during a 
period of about 12 hours. Stirring was continued until separation of 
solid material prevented . adequate mixing. Then the reaction mixture was 
allowed to stand 2 to 3 weeks at 15° to 20° C until no more Grignard re- 
agent was present. The product was treated with ice and dilute hydro- 
chloric acid and the resulting organic material distilled in Column 3« 
After a forerun of ether,, isoamylene, and t-amyl chloride, there was ob- 
tained M*00 ml of crude 2, 3, 3 -trime thylpentane (31-percent yield), which 
"boiled 112° to 115° C. "When refractionated in Column l f the crude paraf- 
fin gave 3600 ml of fractions for which nx> 2 ° = 1.^07^ to 1.1*075 • . Redis- 
tillation of accumulated foreruns from several "batches gave an additional 
quantity of puro material . From several runs a. total of 39 liters of 
pure 2,3,3-trimethylpentane was prepared. 

Early experiments on this preparation were made in which a large ex- 
cess of G-rignard reagent was. assumed to "be desirable, • Trut It was found 



Ik NACA TN No . 12U7 



that the yield of product was actually decreased "by an excess of Grignard 
reagent. For example, In one run In which 72 moles of isopropylmagneeium 
chloride was allowed to react with 57 moles of t-amyl chloride, the yield 
of 2,3,3-trlmethylpentane was only 21 percent, 

2,2,3-Trlmetbylpentane and 2,3,^-Trlmethylpentane 

By fractionation of several cuts of alkylate mixtures, 38.6 liters 
of 2,2,3-trimethylpentane and 37,9 liters of 2,3,^-trimethylpentane were 
prepared. The source materials were alkylates, hydro-codimers, and iso- 
octanes whioh had accumulated at the laboratory. These materials totaled 
approximately 85 gallons. Some of them were partially fractionated, some 
were "as received." 

The unresolved alkylates and residues were roughly fractionated In 
Stills 10 and 11 into concentrates rich in 2,2,3-trimethylpentane and 
2,3,*i--trimethylpentane. These concentrates were redistilled In Column 11. 
Most of the material was obtained by these distillations. Foreruns, in- 
termediates, and afterruns were again fractionated in Stills 1 and 2. 
From a total of kf distillations there were obtained 38*610 ml (at 25° c) 
of 2,2,3-trimethylpentane (nu so = l.t!-026 to 1. 1*029) and 37,955 ml (at 
25° C) of 2,3,^-trimethylpentane (n D 20 = lJtOlU to 1.1*0^5). Physical 
"constants of the two compounds were measured, and agreed well with those 
measured on the pure materials, as reported in references h and 5* 

2, 2,5-Trimethylhexane 

The presence of 2,2,5-trimethylhexane in' isooctane residue was re- 
ported "by Brooks, Cleaton, and Carter in 1937 • (See reference 1.) By 
distillation of an additional 76 liters of this material in Still 10, a 
concentrate rich in this nonane was obtained. This concentrate (1*525 ml> 
b.p. 123° to 125° C, np 20 m I.399 to 1.U00) was refractionated in Still 
1. There was obtained 2005 ml of 2,2,5-trImethylhexane with a refractive- 
Index range of 1.3995 to I.3996. 



2,3,5 -Trime thylhexane 

• This nonane was prepared by hydrogenating 2,3,5-ta , imethyl-2-hexena-, 
which resulted from the reaction of isopropylmagnesium chloride on 1- 
chlbro-2,3-dimethyl-2-butene. There was also formed a small amount of 
2,3,3,^-tetramethyl-l-pentene In this reaction. 

. 2, 3-Dimethyl-l f 3 -butadiene . - Plnacol hydrate, prepared by the method 
of reference 5, was dehydrated to anhydrous pihacol by distillation in 
Columns k to 7. These distillations were carried out at atmospheric 



NACA-'-TN No . 12^7 



15 



Pre-ssure'untii'the head" temperature reached.' 122° -0-, when, the pressure was 
■reduced to 80 millimeters" of mercury. At: this pressure- the .anhydrous 
pinacol distilled at -111° to 11^° C". •: • : - ■'■«-" 



lii' order to ■ determine the optimum conditions for conversion of the 
glycol to 2,3-&imethyl-i,3~'butadiene, a series of- test runs were made. 
The results are "shown in the following table:- 



DEHYDRATION OF PUTACOL TO 2,3>DIMETHn3UTADIE3SE-l,3 
■ .- ■ AKD.PINACOLONE (3,3-I>IMETHyL-2rBOTAlSrONE) ■ 





Bun 


Plnacol 
■taken 
■ > (gm) 


Catalyst .. 


Yield (percent) of - 




Dimethyl- 
"butadiene 


Pi'nacolone 


•■_ 


r- '; 
2- ■ 

V" 


: ^53 

• 500 

•500 

..'•500 


1.5 grams' ^8-percent hydro - 
bromic- acid 

5 .0 grams p -naphthalene sul- 
■ fonic .acid 

5 .0 -grams p- toluene : sulfonic 
' acid : :.■.■■■. . i 

7*0 grams aniline hydro- 
-. bromide 


h5 •'.', 
18 


. ','19 

-3fc 

..".'•31 

15 



In -thsse experiments, the pinacol was refluxed, with .-the .catalyst in Col- 
umns 5 or 7» The product of each run was. washed, dried, and. distilled in 
Column 6 for analysis ■. ■ From the results . of . .these experiments, it was 
"concluded that -li-8-percent hydjsoTsromic acid .was ;,the- he.st catalyst of those 
tried for this dehydration. ; By dehydrating sever^. "batches of pinacol 
(.2 .5 to. 3 .0 • kg per hatch) ,- 17 A .liters .of 2, 3.-*dimethyl-i,.3-.hutadiene was 
propared which "boiled 68.5 to 71-.5.° a-b 75? mil-lime ters...- 

* ■•■•■•■ ■l^Chloro-2 . 3rdtmethyl-2-butene .- ■ The addition of hydrogen chloride 
to: 2,3*&imethylT&,3-hu.tadiene. was accomplished -in the apparatus described 
in -reference -2* .The reaction chambers- were kept at. -30° C, and dry hy- 
drogen chloride and alk&diene added simultaneously , The daily output of 
the apparatus was 1.0 to 1.5 liters of chloride. The product was froed 
of dissolved hydrogen chloride by aeration with carbon dioxide and stored 
over sodium carbonate. Distillation analysis showed that the reaction 
was practically quantitative. The product used for further synthesis 
foiled at 32° C at lj-5 millimeters of mercury. 



16 NACA TN No . 12^7 

2, 3,3-Trimethyl-2-hexene .- To an ether solution of 62 mole's of led-' 
propylmagnesium chloride was added 7.32 kilograms of l-chloro-2,3-dimethyl- 
2-butene. The reaction mixture 'became very viscous, and it was necessary 
to add more ether at intervals* The reaction was worked up after k days 
and the organic material was dried, the ether removed, and the crude res- 
idue distilled through Column 3 (b.p, 70° to 71° C at 90 mm, 
np 20 «» 1A299). Although there was no appreciable forerun, a large amount 
of high-boiling material (175° to 200° C) was present. This material was 
not identified, hut is presumed to he polymers (dimers and trimers) of 
the alkadiene formed under the influence of the Grignard reagent* 

The crude 2,3,5-trimethyl-2-hexene contained a considerable quantity 
of chloride, .the greater part of which was removed by boiling with alco- 
holic potassium hydroxide. Hydrogenation of the crude alkene gave 2,3,5- 
trimethylhexane, which was filtered through silica gel and distilled in 
Column 3 • From 2500 ml of material, there were obtained 900 ml which 

boiled 131-.9 P C (nr> 20 = 1.1&60 to l.k06l) and 50 ml of a hydrocarbon 
which boiled l4l*9° C (n^ 20 ■ 1.U218) . The latter was identified as 
2,3,3j**--tetramethylpentane by comparison with a sample prepared in another 
manner. A residue of about 1 liter which boiled above I65 C resulted 
from this distillation. This residue was probably formed by the action 
of potassium hydroxide or hydrogenation catalyst on the unsaturated halide 
which was present in the crude olefin. Obviously, most of the Grignard 
reagent was. dissipated in side reactions rather than by coupling with -the 
chloride in the expected manner. This tendency could possibly have been ■ 
decreased by carrying out the reaction in a more dilute solution. 

This preparation was made in I939 at the suggestion of Dr. C. E. 
Boord of Ohio State University. The goal was the preparation of 2,3,5* 
trimethylhexane and 2,3,3,U-tetramethylpentane. The reaction yielded 
about eighteen parts of the former to one part of the latter. These two 
hydrocarbons probably resulted from the action of the Grignard reagent on 
two isomers of 2,3-dimethylchlorobutene. These two isomers probably were ' 
l-chloro-2,3-dimethyl-2-butene, formed by 1,4 addition of hydrogen chlo- 
ride to the diolefin, and 3-chloro-2,3-dimethyl-l-butene, formed by 1,2 
addition. The former chloride would be expected to react with isopropyl- 
magnesium chloride to give 2,3,5-trimethyl-2-hexene, and the latter chlo- 
ride to to give 2,3,3,^-tetramethyl-l-pentene. 

E. T. Cline has made a study of this reaction (reference 14), in 
which hydrogen bromide, rather than hydrogen chloride, was used. He ob- 
tained a ratio of alkenes of 1.6 parts of 2,3,5-trimethyl-2-hexene to 1 
part of 2,3,3,'4-tetramethyl-lrpentene.. 



NACA TN Ub.' 12U7 17 

2,2,k-Trimethylhexane 

■ In 1937, Brooks, Cleaton, and Carter (reference l) isolated an un- 
known nonane from the residue obtained in the distillation of isooctan© 
(2,2,^-trimethylpentane), which was tentatively identified as 2,2,k~ 
trimethylhexane . In order to establish the identity of this hydrocarbon. 
a sample of 2, 2, ^-trimethylhexane was prepared, and a comparison of phys- 
ical properties made. 

Diisobutylene was oxidized by sodium dichromate, as described in 
reference 15 by Whitmore, Homeyer, and Trent, to give trimethylacetic 
acid and l4-,lt--dimethyl-2-pentanone (methylneopentyl ketone) . The oxida- 
tion of diisobutylene isomers is diBcussed more fully in later sections. 

To 7.0 moles of ethylmagnesium chloride in l^O ml of ether solution 
was added 7^2 grams (6.5. moles) of lt,^-dimethyl-2-pentanone (b.p. 12U° C 
at 76O mm Hg, nj) 2 ° = l.li038) in 800 ml of dry ether. The reaction mixture 
was allowed to Btand at xoom temperature for 35 hours, refluxed for 6 
hours, and then worked up in the standard manner. The organic material 
was washed, dried, and distilled in Column k. In. addition to ether and 
recovered ketone, lK>9 grams (2.9 moles) of 3,5,5-trimethyl-3-hexanol and 
Bk grains (0 .6* mole) of nonenes resulting from premature dehydration of 
the carbinbl were obtained. The purified carbinol was dehydrated by heat- 
ing with P-naphthalene sulfonic acid (1 gram) to give a mixture of alkenes 
which boiled 127° to 132° C. The yield was 335 grams (91 percent). This 
alkene mixture has been analyzed by Whitmore and Cook ( reference 16) who 
found by ozonolysis that it contained approximately three parts of 3,5,5- 
trimethyl-2-hexene, one part of 2-ethyl-li-,4-dimethyl-l-pentene, and a 
trace of 3,5,5-trimethyl-3-hexene. All these compounds give the same 
alkane when hydrogenated, so no attempt was made to separate them. 

' The alkenes were hydrogenated, and the product filtered through 
silica gel and distilled in Column 5. ■ The middle JO percent of the dis- 
tillate, which distilled at a constant temperature, was redistilled v in 
the same column, the middle 25 percent of the distillate from the latter 
distillation was used in the measurement of physical properties. The 
properties of the synthetic material are given in table 2 and are compared 
in the following table with the properties of 2, 2, h~ trimethylhexane, which 
was isolated. by the present authors. The identity of the two is proved 
by data on the freezing point- of the 50 :50 mixture . 



18 



NACA TN No . 1247 



Property 


Synthetic material 
2, 2, 4- trlmethylhexane 


Fraction from 
isooctane residue 
(reference 1) 


Boiling point at 760 mm Hg, °C 


126.54 


126.51 


Change in "boiling point with 
pressure, °c/mm Hg 


00 .0503 


... 


Freezing point, °C 


-123 .4 (mp) 


-129.53 


Freezing point of mixture, °C 


-124.19 


-124.19 


Befractive index, nj) 20 


1.4033 


1.1*0312 


TVrw 25 


1.4010 





Density, gm/ml, d 2 ° 


0.7156 


80 .7153 


d 25 


O.7H8 


... 



^he published density, 0.7048 (reference l) of the material Isolated 
from isooctano residue was in error. A recalculation of the original data 
gave O.7153, redetermination gave 0.715k. 



2,2-Dimethyl-3-Ethylpentane 

The synthesis of 2,2-dimethyl-3-ethylpentane was carried out in the 
following steps: (a) Reaction of t-butylmagne slum chloride with carbon 
dioxide to give the Grignard complex of trimethylacetlc acid, (Td) reac- 
tion of this complex with ethylmagneslum chloride to produce 2,2-dimethyl- 
3-ethyl-3-pentanol, (c) dehydration of the carblnol to 4,4-dimethyl-3- 
ethyl-2-pentene, and (d) hydrogenation of the olefin to 2,2-dimethyl-3- 
ethylpentane . 

To 50.2 moles of t-butylmagnesium chloride in 18 liters of ether, 
cooled to 5° C, was added 3 kilograms of solid carbon dioxide in small 
pieces while the' reaction mixture was being stirred. Stirring was con- 
tinued while the mixture came to room temperature and while it was heated 
to reflux for 2 hours. It was then cooled and 104 moles of ethylmagne- 
sium chloride in 20 liters of ether was added slowly. After addition was 
complete, the mixture was stirred for 6 hours and allowed to stand at 
room temperature for 2 days. The product was distilled In Column 6. 
From this distillation was obtained 3U85 grams (48.2 percent yield) of 
cartonol (la .p. 90 to 95° C at 50 mm Hg,. 151° to 176 C' at 756 mm Hg, 

n D so ■ 1.4417, d 2 ° =0.851). The carhinol was dehydrated "by heating 



NACA «HT No. 12^7 



19 



with 3 -naphthalene sulfonic acid to give 3600 ml of alkene. Fraction- 
ation of the crude alkene in Column 5 gave 2680 ml of .purified k,h- 
dlmethyl-3-ethyl-2-pentene* .The alkene was hydrogenated, and the product 
filtered through silica gel and distilled in Column 1. From this distil- 
lation 3.650 ml of •constant-'boiling 2,2-dimethyl-3-ethylpentane 
(RD 20 ■ 1.U1225 to 1A1230) was obtained. 



2, ^-Dimethyl- 3-lthylpentane 

Preparation, of 2,U-dimethyl-3-ethylpentane was accomplished by hydro- 
■'genation of the alkenes which resulted from the dehydration of 2,k- 
; -dimethyl- 3-ethyl-3-pentanol". The carbinol resulted from the action of 
ethylmagnesium chloride on 2, ^-dimethyl- 3 -psntanone (diisopropyl ketone). 

To 76.2. .moles of ethylmagnesium chloride was added 75 moles of ' 2, it- 
dimethyl- 3-pentanone during 2 days. The product was recovered "by addi- 
tion of ice and ammonium chloride to the. reaction mixture, and "by subse- 
quent distillation gave 5650 grams (52.3 percent) of '2,^-dimethyl-3-ethyl- 
3-pentanol. A pure sample was obtained "by redistillation of the "best 
portion of the crude. 

* ' 

The carhinol- was dehydrated with 3 -naphthalene sulfonic acid to give 
6110 ml of crude alkene mixture. A charge of 2 liters of the dehydration 
product was fractionated in Column 5 for analysis. The individual olefins 
were recovered in the ratio of 77 percent of the lower-boiling 2,k- 
dimethyl- 3- ethyl- 2-pentene to 23 percent of the higher-boiling li-methyl- 
3-isopropyl-2-pentene . A sample of each of these Isomers was redistilled 
for determination of physical constants . The values obtained were : 



Property 


2, ii-Dimethyl- ' 
3-ethyl-2- 
pentene 


4-Methyl-3- 

isopropyl-2- 

pentene 


Boiling point at 760 am Hg, °C 


•130.5 


138.7 ' 


Refractive index, n.j) ao 


1.U227 


I.U3U9 


*D aS 


l.Uaoii.. 


l.lf-326 .:■ 


Density,' d 20 


0.7^33 


0.758U 


d a5 . 


.7385 


0.7550 • 



Hydrogenation of samples of "both alkenes yielded the same alkane. 
The alkene mixture (b.p. 128° to lUo° C) was hydrogenated and the result- 
ing product distilled, in Column h. ' The -portion' "boiling I36 to-139° C 
was filtered through silica gel and refractionate'd in Column 1. 



20 WACA TN No . 12^7 

In 19^5 "the preparation was repeated on a somewhat larger scale. 
For this preparation, 2, ^-dimethyl- 3-pentanone was fractionated' in Still 
11. Only the purest fractions obtained (Id .p. 12ij-.6° to 12*4- .7° C, 

njj 20 = J.Uq'15 to 1.^017} were used in the subsequent synthesis.- The. car- 
ls inol was, the product of ' reaction- of the-Grignard reagent prepared from 
260 moles of ethyl chloride with 223 moles of redistilled ketone. .The 
reaction product was -distilled in Column 21 .'until the head temperature 
was 130° C. A sample (1660 grams) of the residue' was< distilled in Column 
k. From this distillation. there 'were obtained 1130 grams of pure carbi- 
nol (2,U-dimethyl-3-ethyl-3-pentanol, b.p. 9^.5° to 95 .0° C at kj mm Hg) 
and about 200 grams of less pure material. A sample from the middle cut 
of this distillation .was reserved for.-physicaT constants measurements. 

: The rest of the undi stilled residue was dehydrated, with; sfrrnaphththalreie 
sulfonic acid, and- the dehydration products were. washed/ driedjo and- dis- 
tilled in Column 11.. Analysis of the distillation curve showed the- pres- 
ence of 77 volume percent (13 A' liters) -of lower-toiling- olef.in>-,and 23 
volume 'percent (U.O liters) of the higher-boiling isomer. In this distil- 
lation a "best sample from each .of the. plateaus was reserved, and redis- 
tilled in Column 17* for physical-constants measurements. Hydrogenation 
of- the- olefins was carried out as previously described. The paraffin was 
fractionated in Columns 17, 18, 19, and 20. There was obtained lljSoo ml 
of pure hydrocarbon for engine tests. Physical constants of materials 
synthesized in this later preparation are given in table 2. ' 

2 , 2 , 3 - 3-Te trame thylpent ane < Te trane ) 1 

The synthesis of 2,2,3,3-tetramethylpentane (a new compound desig- 
nated- tetrahe) was first accomplished in 19^0 (October-December). : The re- 
daction involved (a) preparation of 2,3,3-trimethyl-2-butanol ( trlptanol) 
'from 3,3-diirtethyl-2-but»aiione (-pinacolone) and methylmagnesium bromide, 
(b) reaction of this carlo inol with hydrochloric .acid to. give 2rchloro- 
: 2,3,3 -trimetii.ylbutane (triptyl chloride), and (c) reaction of the chlo- 
' ride with ethylmagnesium chloride to give the nonane and 2, 3,3-trimethyl- 
• 1-butene (triptene) . 

From 82 mplee of pinacolone and 6% moles of methylmagnesium bromide, 
56 ;-5 moles of 2,3,3-trimethyl-2-butanol was prepared. This carbinol was 
dissolved in ether, and the solution shaken with several portions .of con- 
centrated hydrochloric acid. Samples of the ether solution were removed 
periodically. The sublimation point of the crude chloride from these 
samples- rose to 131° to 133° C . Recrystallized chloride was found to sub- 
lime at 133° C. The chloride solution was washed, dried, .and added to 115 
moles of ethylmagnesium chloride. The mixture was stirred for 3 hours and 
then allowed to stand for .h weeks at room temperature . 



^•Compounds designated with asterisks -are. believed -to be new compounds. 



1 . .' v * 



NACA TN No. 12it7 21 

After the reaction mixture vas worked up, the organic material was 
distilled in Column 6, and yielded 2100 ml of recovered triptene (tri- 
methylbutene) and 1900 ml of crude 2,2,3,3-tetramethylpentane, which was 
contaminated "by a considerable amount of triptanol. The carbinol was 
filtered off as the hydrate, and the filtrate dried and filtered through 
silica gel. 'The volume of nonane recovered was 1250 ml, which represents 
a yield of 9 percent, based on the original pinacolone. Distillation of 
this material in Column k gave IO87 ml of hydrocarbon which was collected 
at 88.6° to 88.7 C at 159 millimeters of mercury. A portion of this ma- 
terial was recrystallized repeatedly, until the refractive index and 
freezing point. were unchanged by further crystallization. Physical con- 
stants were measured on this. sample. A second run of this preparation 
was made in March I9UJL/ in which' recrystallized triptyl chlaride was 
reacted with an equimolar quantity of the Grignard reagent. In this case 
the yield was increased to 22 percent, "based on the chloride. 

Procurement of 10 gallons of this hydrocarbon was undertaken in 
I9IH. Part of this (2.9 gal) was prepared at Ohio State University the 
rest was prepared in these laboratories. This large-scale preparation 
was carried out by a modification of the technique developed at Ohio 
State University. The chloride was added to the Grignard reagent in 
eight equal portions, in 8 successive days, while the reaction mixture 
was kept at 35° C. 

An improved method was devised for the preparation of the large quan- 
tities of triptyl chloride necessary for this synthesis. The equipment 
consisted of three reactors, made from 30 -inch lengths of 12- inch pipe, 
closed at both ends with companion and blind flanges. One end of each re- 
actor was fitted with a small steel valve (l/h- in.) . These reactors were 
refrigerated (-30° C) and were connected to a manifold through which hy- 
drogen chloride could be admitted to eaGh. The reactors were charged with 
triptene in wide -mouth bottles. The flanges of .the reactors were secured 
by bolts and the reactors were allowed to stand until cold. Hydrogen 
chloride was then admitted until the pressure was 100 to 120 psi. The 
pressure gradually fell as the gas reacted until the pressure was about 
50 to 60 psi. . Then the process was repeated until there was no, appreci- 
able change in pressure during an hour. The excess gas was released, the 
system purged with dry air, and the product removed. The yield was prac- 
tically quantitative . The product was uncolored and contained a. small 
amount of excess hydrogen chloride. This excess was converted to alkyl 
chloride by adding a small amount of olefin to each jar and allowing to 
stand until reacted. By means of this technique, 20 to 35 liters of 
triptene was converted to the chloride in 1 working day. 

To 300 moles of ethyl magnesium chloride there was added 360 moles of 
triptyl chloride in eight equal portions during 8 days. During this time, 
the reaction mixture was heated to reflux temperature and stirred. At the 
end of 2 to h additional days, when all the Grignard reagent had reacted, 



22 NACA Tff No. 12Vf 



the mixture was worked tip with ice and hydrochloric acid and washed four 
times with water. Distillation of the ether, and of most of the triptene 
was carried out from the reaction kettle. The distillate was dried and 
redistilled in Column 12 or 13 for recovery of triptene • 

The residue in the reaction kettle was "boiled with sodium propylate 
in propyl alcohol until the product was subetatially free of chloride. 
After the product was washed,, it was steam distilled, and the distillate 
dried end "boiled with alcoholic silver nitrate to remove the last traces 
of chloride. Then the product was filtered, washed several times, dried, 
and distilled in Columns 11, 18, 19, and 20, Prom two runs as doscribed, 
which were worked up together, there was. obtained 1^.92 kilograms ( 116.6 
moles) of tetrane which was 99*6 mole percent pure. This represents a 
yield of 19 .h percent. A total of 21.7 kilograms was prepared by this 
method . 

2,2,3,t-Tetramethylpentane and 2,3,3,U-Tetramethylpentane 

The first preparation of these two nonanes was accomplished in June 
19^1 lay hydrogenation of the alkenes (reference 17) formed "by the dehydra- 
tion of 2,2,3,U~tetramethyl-3-pentanol. The carbinol wab prepared by the 
reaction between methylmagnesium bromide and 2,2,U-trimethyl-3-pentanone. 
This ketone was the result of oxidation of 2,2,l4--trimethyl-3-pentanol, 
one of the products resulting from the action of t-butylmagnesium chloride 
on isobutyraldehyde . 

The method of reference 17 was used to prepare 2,2,^-trimethyl-3- 
pentanol. To 55 moles of t-butylmagnesium chloride was added 3960 grams 
(55 moles) of isobutyraldehyde. Distillation of the organic reaction 
products gave U290 grams (33 moles, 60-percent yield) of 2,2,t»-trimethyl- 
3-pentanol. The carbinol was oxidized to pentamethylacetone (2,2,1*-- 
trimethyl-3-pentanone) with potassium dichromate and sulfuric acid, by 
method of Faworsky. (See reference 18.) From 32 moles of carbinol, 
there was obtainod 3150 grams (2^.6 moles, 77-percent yield) of ketone, 
which was distilled in Column 5. 

The 2,2,*t--trimethyl-3-pentanone (2k. 6 moles) in 6 liters of ether 
was reacted with 26 moles of methylmagnesium bromide, and the product dis- 
tilled in Column 5 until the temperature reached 1^3° C. At this point 
dehydration of the carbinol was beginning to take place, so the distilla- 
tion was interrupted, and the clear, slightly yellow residue (2950 ml) 
was dehydrated with (5 -naphthalene sulfonic acid. 

: From the dehydration there resulted 2lH0 ml of alkene mixture, which 
was dried and distilled in Column 3. The following fractions were ob- 
tained: 



NACA TN No . 18^7 



23 



Fraction 


Boiling Range 
(Head temperature) 

(°c) 


Volume 
(ml) 


Identification 


1 
2 

3 
k 

5 


91 to 119 
119 to 12k 

12U to 129 
130 to 135 

>135 


23 

1550 

200 
600 

120 


Forerun 
3,3-Dimethyl-2- 

isopropyl-1-butene 
Intermediate 
2,3, 3, ^-Tetramethyl- 

1-pentene 
Residue 



Fractions 2, *3, and k represent a combined yield of alkenes of 15 .9 
moles (65 percent, based on 2,2,^-trimethyl-3-pentanone) . Samples from 
the middle of the plateaus represented "by fractions 2 and h were reserved 
for physical-constants measurements. No attempt was made to isolate 
2,3,li,lt-t6tramethyl-2-pentene, a very small quantity of which was found 
"by Vhitmore and Laughlin in ' reference 17 • 

The alkene fraction which distilled 119° to 12lt-° C was hydrogenated, 
and the product was filtered through silica gel and distilled in "Column 
3. There was obtained 1G7Q ml of hydrocarbon which "boiled 133.7° to 
13^.1° C, nj) 20 (uncorrected) = iJklhJ to 1JH50. ("Uncorrected" means 
no correction for possible instrument error.) Redistillation of this ma- 
terial gave 930 ml collected at 133 .8° C. Physical constants were "deter- 
mined on a Bample from the. center of this fraction. 

The alkene fraction k was treated in like manner, ' and yielded 3^7 ml 
of jrialterial 'Qollected at 1^2° C (uncorrected), fractions .'of which showed 
a, refractive -index range np 20 (uncorrected) of I.U219 to l.lj-220. A., 
sample from 'this distillation was reserved/for" determination' of physical 
constants. . All .intermediate fractions, foreruns, residues, and material 
eluted from silica gel were hydrpgenated and distilled in Column 8, In 
this way, there were obtained an additional 200 ml of 2,-2,3,Vtetramethyl- 
pentane and lk-5 'mi of 2,3,3,lt-tetemiethylpentane, 

Tests on these- two hydrocarbons demonstrated the advisability of pre- 
paring larger quantities. Consequently, 10 gallons of each was synthe- 
sized at Pennsylvania State College . These hydrocarbons were purified in 
these laboratories for engine tests by 'distillation in Column- 1. New 
pure samples f.or measurement of physical • constants ' were obtained concur- 
rently. The. improved data are given in table 2» 



2>+ NAOA TN No. 12*1-7 



Dimethyl-Zinc Synthesis of Three Tetramethylpentenes 

An olefin co-polymer fraction containing 3, 1 *, t '--trimethyl-2-pentene 
and 2,3,^-trimethyl-2-pentene, was reacted with dry hydrogen chloride un- 
til about 60 percent of the oiofin waB converted to chloride. This 
chloride- olefin mixture was treated with dimethyl zinc in a solvent of 
hydrogenated co-dimer, which contained 2,2,3- and 2,3,^-trimethylpentanes. 
The resultant product was hydrogenated to a mixture of hydrocarbons, all 
known to have superior characteristics. This study led'tft-'the^synibheses 
of these compounds in a pure state by this method. 

Secondary and tertiary butyl alcohols were co-polymerized in the 
presence of sulfuric acid in the manner described in reference 19« A 
portion of the product was analyzed by distillation in Column 1 and was 
found to contain the diisobutylenes, 2,^,^-trimethyl-l- and -2-pentenes 
(25 percent), 3,lj-,lj-trimethyl-2-pentene (23 percent), 2,3,U~trimethyl-2~ 
pentene (37 percent), and higher-boiling material (15 percent). The rest 
of the olefin mixture was routihly separated by distillation in Column 5» 
The fractions which boiled 107° to 120° C amounted to 97^0 grams and con- 
sisted of 2,3,4-trimethyl-2-peritene and 3,^,^-trimethyl-2-pentene aB ma.'Jor 
components. Part of this fraction (6300 grams) was fractionated in Col- 
umn 2. By this distillation there were obtained' 1150 grams of 3,^,^- 
trimethyl-2-pentene (nj> 20 - IA23O, np 25 « 1.1+205, d 2 ° = 0.7392, 
d 25 = 0.7350, b.p. 112.1° to 112.8° C.) .and 1865 grams of 2,3,^-trimethyl- 
2-pentene (n D 20 » 1A275, nr 25 = IA250, d 2 ° = ,0.7^, d S5 - 0.7391; h.p. 
116. 3° to. 116.'5° C). 

These two alkenes were reacted separately with hydrogen chloride at 
-6o° C in an apparatus described in reference 2 until approximately 60 
percont of the alkene had been converted ..to alfcyl chloride . The products 
were washed, .dried, and fractionated in .Columen 3» In this way, 7l6 grams 
of constant-boiling 3-chloro-2,2,3-trimethylpentane was obtained from the 
3,.U,^-trimethyl-2-pentene. The chloride from 2,3,if--trimethyl-2-pe>ntene 
(lA.10 grams) was probably a mixture of 2-chloro-2,3,t-trimethylpentane 
and 3-chloro-2,3>^-trimethylpentane. Since these two chlorides were ex- 
pected to yield two different nonanes (by reaction with dimethyl zinc), 
with boiling points differing by about 8° C, no attempt was made to sepa- 
rate the chloride mixture. Physical , constants measured on the chlorides 
are. included in table 2. 

2,2,3. 3-Tetramsthylpentane . - In the apparatus, and by the technique 
described previously, 4- .15 moles (6lk grams), of 3-chloro-2.2,3-trimothyl- 
pentahe in 700 ml of isooctane (2,2,4-trimethylpentane, S-k reference 
fuel) was allowed to react with the dimethyl zinc from 7.75 moles' of 
methyl iodide. The dimethyl zinc was in a solution with 500 ml of iso- 
ootane. The bath temperature for the reaction was 7° C. The product was 
boiled for 2 hours with 5-percent potassium hydroxide in alcohol, washed, 
and fractionated in Column k. This distillation gave: 



NACA TN No . 1247 



25 



Fraction 



Boiling range 
(Head temperature) 
(°C) 



"Volume 
(ml) 



Refractive index, np 



20 



1 
2 
to 

5 
6 

7 



96 to 100 

100 to 110 

110 to 116 

116 to 138.6 

138.6 to 1U0.3 

140.3 



1130 

65 

231 

27 

39 

150 



1.3918 
1.1*059 
1.4195 to 1.4225 
1.4226 
1.4226 
1.4233 



Distillation, of the residue was continued in Still 8 and gave : 



8 j 140.3 

9 (Residue) >l40.3 



77 
10 



1.4232 
1.4379 



" Fraction 1 was. recovered solvent. Alkene "by-products of the reac- 
tion, formed "by dehydrochlorination of the alkyl chloride, were contained 
.in fractions 2 to 5» By the low refractive indices of these fractions, 
it is indicated that this material consisted mostly of 3>4,4-trimetbyl- 
2-pentene. The yield of 2,2,3,3-tetramethylpentane (fractions 6, 7, • and 
8) amounted to 37 «7 -percent "based on alkyl chloride. ' Fraction 7 > .after 
filtration through silica gel', had the following properties: freezing 
point, -11. 85 C, toiling point, 140.20° to 140.23° C at 760 millimeters 
'of mercury,- refractive index, n^ 20 = 1.4233, np 25 = 1.4211j density, 
d 20 ss O.7565, d 35 -sb 0.7527. " It may "be seen that the product was of high 
purity whon these properties are compared with those of the- pure sample, 
as listed in tahle 2 . "The freezing point indicates a purity of about 
99.5 mole percent. . r 

2, 2, 3, 4-. 'and 2,3, 3 ,4-Tetramethylpentanes .- By use- of the same proced- 
ure as. described, two runs were made in which a total of 8.35 moles of 
the mixture of 2-, arid 3-chloro-2 jr 3,4-trimettiyipentanes was reacted, at 
10° C,with the dimethyl zinc from 15»5 moles of methyl iodide. The com- 
bined products were refluxed with alcoholic potassium -hydroxide, washed, 
dried, and distilled in Column 4. This operation gave: 



26 



naca'tn No. 121+7 



Fraction 


Boiling range 
(Head temperature) 

<°cf 


Volume 
(ml) 


Refractive index, nj) 20 


1 
2' 
3 to h 

5 

6 to 8 

9 

10 


95 to 100 
100 to 115 
115 to 119 
119 to 130 
130.0 to 133.5 
' 133.5 tb 13U.O 
13U to 1U0 


2051 
116 
kho 
31 
139 
138 

■ 6k 


1.3917 
l.l+080 
' 1. 1V269 to 1. 1+267 
1.1+219 
I.I+I58 to 1.1+150 
1.1H52 
I.I+I83 


The residue was distilled in Still 8, and gave: 


Il- 
ls 

13 
li+ 
15 (Bee 


lUo.O to 1*1-1.5 

11+1.5 to 11+2.0 

11+2.0 to 1I+3.O 

li+3 to 165 


10 
60 
20 
10 
83 


1 .1+212 
1.1+218 
1.1+221 
1 .^271 
1 .1+570 



Fraction 1 vas recovered isooctane; fractions 3 to 1+ were alkene "by- 
products, indicated to "be mostly 2,3,l+-trimethyl-2-pentene "by the refrac- 
tive indices. The total yield of tetramethylpentanes (fractions 6 to ll+) 
amounted to 30 percent, "based on alkyl chloride. These tetramethylpen- 
tanes consisted of about 71 percent of 2j2,3,l+-tetramethylpentane and 
a"bout 29 percent of 2,3,3,l+-tetramethylpentane. 

Fraction 9, after filtration through silica gel, had the following 
properties: freezing point, -122 .5!+° C, toiling point, 133.3° to 133.1+ C 
at 760 millimeters of mercury, refraotive index, njj 2 ° » 1.1+11+8, 
nu 25 » 1. 1+127 j density, d £ ° « 0.7397, d 25 - 0.735*'. These values are in 
agreement with those reported for the pure 2,2,3,5-tetramethylpentane in 
table 2. Fraction 12 was filtered through silica gel, and the eluent used 
for measurement of physical properties. These properties were found to 
"be : tolling point, lf+1 .3° to l&l .1+° C at 760 millimeters of mercury,- re- 
fractive index, nu 20 = 1.1+217, n D 25 = I.I+I96, density, d 20 =» 0.75^5, 
d 25 s 0.7512. These data agree with those reported for purer 2,3,3,k- 
tetramothylpentane in table 2. 

A tetramothylpentane, assumed to "be 2,3,3,l+-tetramethylpentane, was 
prepared "by Dinerstein (reference 20) in 19^0, "by action of dimethyl zinc 
on 3-chloro-2,3,l+-trimethylpentane. Later work "by Enyeart (reference 21 
and "by the present authors shows that the hydrocarbon described by 
Dinerstein was 2,2,3,l+-tetramethylpentane. 



NACA TN No. 12lf-T 27 

*2, ^-I)imethl-3-lBopropylpentane (Trilsopropylmethane) 

The recent preparations of triisonropylcarbinol "by the action of 
isopropyl lithium on 2,l*--dimethyl-3-pentanone (diisopropyl ketone) (see 
reference 22) and "by the action of isopropyl chloride on diisopropyl 
ketone in the presence of sodium (see reference 23) have made available 
a method for synthesizing .triisopropylmethane (2,J+Tdim6thyl-3-ieopropyl-: 
pentane). A quantity of this compound has "been prepared by the use of 
isopropyl lithium. 

Preliminary work on this reaction was performed in several small- 
scale experiments, in each of which 10 gram atoms of lithium, 6.5 moles ■ 
of isopropyl chloride, 5»^ moles of diisopropyl ketone, and 2000 ml of 
solvent were used. During this study, it was found that technical 2,2,H- 
trimethylpentane (isooctane) served admirably as a sol-vent when its iise 
was augmented "by efficient stirring and external cooling of the reaction 
mixture. Kb preliminary purification of the solvent was necessary and 
the hazards accompanying its use are much less than those of petroleum 
ether, used "by the origin«il investigators. (See reference 22.) 

The preparation of the considerable quantities of finely divided 
lithium required was expedited "by the use of a small laboratory rolling 
mill. While the lithium was "being worked in the mill it was, lubricated 
and coated with a mixture of 8o-percent isooctane and 20-percent light 
mineral oil applied "by means of an oil can. This technique tended to 
prevent the lithium from sticking to the rolls and also prevented exces- 
sive oxide formation. The rolled pieces, about 0.003 inch thick, were 
cut into ribbons and then into squares in large shallow pan under iso- 
octane. 

The yields in all the preliminary runs amounted to 18 to^ 22 percent 
of carbinol. Wo appreciable change in yield was experienced when the 
reaction between isopropyl lithium and diisopropyl ketone w*,s carried out 
at 99° C, the temperature of boiling isooctane, rather, than- ai 35° C, 
the temperature used by the original investigators. 

. -After the technique of 'handling the reaction had been sufficiently 
developed, a large run was- carried out in the 50-gallon stainless-steel 
kettle. Tha total' quantity of reactants used was: 159 gram atoms (1.10 
kg) cf lithium, 115 moles (9 .03 kg) of isopropyl chloride, 80 moles (9.13 
kg) of diisopropyl ketone, and 55 liters- of isooctane. The quantity of 
isopropyl chloride was relatively larger than that used by the original 
investigators in order that a minimum amount of lithium be left unreacted 
and that any loss occurring through the reflux condenser be replenished. 
The diisopropyl ketone was constant-boiling material obtained by redis- 
tillation of the commercial product in Still 11. 



28 NACA TN Ho. 12^7 

The kettle was flushed with nitrogen and charged with 31 liters of 
iaooctane. A"bout half the lithium was added and the reaction started "by 
the addition of 1 liter of isopi-opyl chloride in 1 liter of isooctane, 
and "by warming the (Jacket to 35° C . The remainder of- the lithium was 
added in three additional charges during the next 2g- days. During the 
first 3 days, a mixture of the remainder of the isopropyl chloride in an 
equal volume of isooctane was added in four charges, 

A solution of di isopropyl ketone in 11 ,k liters of isooctane was 
added during 8 hours, while the reaction temperature was held at k^° to 
60° C. After addition was complete, the mixture was warmed and stirred 
for 5 hours, after which it was cooled. Decomposition of the reaction 
mixture was effected "by the addition of 25 pounds of cracked ice, fol- 
lowed lay a solution of 11 pounds of ammonium chloride in 5 gallons of 
water. The aqueous layer was removed, and the organic layer washed five 
times, each time with 3 to 5 gallons of water, after which it was with- 
drawn and dried overnight with potassium carbonate. 

Fractionation of the product in Column 6 gave: recovered isooctane, 
diisopropyl ketone, toiling point 121° to 126° C, 2355 grains > intermediate 
fractions, 2kO grams; and triisopropylcarMnol, "boiling point 10U° to 
110° C at 50 to 55 millimeters of mercury, 2576 grams. This represents a 
yield of 20.4 percent "based on the diisopropyl ketone added. A prrt of 
the triisopropylcarMnol was redistilled, and a pure sample col.^.cfced from 
the middle of this distillation for the measurement of physical constants. 

The carMnol ' was dehydrabed "by distillation from anhydrous copper 
sulfate. From 16 -moles of triisopropylcarMnol, Ik.k moles (90 percent) 
of crude 2,lt-dimethyl-3-isopropyl-2-pentene, was obtained. Water recovery 
amounted to 80 percent. The crude olefin was dried over calcium chloride 
and distilled in Column 6, from which 1372 grams of material, which toiled 
153 .2° to 153.6° C at 756 to 759 millimeters of mercury, n^ = 1A368 
to 1A371 (all values uncorrected), was collected. A sample was removed 
from the middle of the distillation for the measurement of physical con- 
stants . 

The olefin was hydrogenated, and distilled in Column 6, and gave 
1100 grams (80 percent) of constant-hoiling material, "boiling point 
156 .5° C at 7^9 millimeters of mercury, n D £ °= l.ii-234 to l.lj-236* (all val- 
ues uncorrected) . This material contained a trace of olefin which was 
removed "by repeated filtration through silica gel. Befractionation under 
reduced pressure afforded the means of obtaining a pure sample for 
physical-constants measurements. 



NACA IN Wo. 12^7 29 

- # 

Pentamethylpentanes 

2*2.3,3' *<-Pent ame thylpentane . - The first preparation of 2,2,3,3, U- 
pentamethylpentanewas carried out in February X9^ "by the reaction 
"between 2-chloro-2, 3,3-trimethylbutane and isopropylmagneslum chloride. 

To 30.5 moles of isopropyl magnesium chloride in 10.53 liters of 
ether solution, there was added, at room temperature, 26. h moles of 2- 
chloro-2,3,3-trimethylbutane (sublimation point 132.7° to 13lj-° C) in 3.5 
liters of ether. After standing for 3 weeks at 15° to 20° C, the reac- 
tion mixture was worked" up in the usual manner* The product, distilled 
in Column': 6 ; gave: 

1^.8 moles of 2,3,3-trimethyl-l-"butene, formed "by dehydro- 
■■ chlorination of 2-chldro-2,3,3-trimethylDutane 

0*1 mole of 2-propanol, formed "by oxidation of the G-rignard 
reagent, found in an azeotrope with 2,3j3-trimethyl-l- 
"butene . 

2.2 moles of recovered 2-chloro-2,3,3-trimethyl'butane 

3.1 moles of 2,3,3-trimethyl-2-"butanol, presumably "by hydrol-. 
■ ysls of the chloride 

1.05 moles of crude 2,2,3,3,4-pentamethylpentane 

This represents a yield of k,0 percent. Another run, in which I9.V3 moles 
of the -chloride was used and which was kept at. 5° C for 3 weeks, then, at 
room temperature for 2 weeks, yielded 0.6 mole of additional crude (3.1- 
percent yield) . 

The combined yield of crude material (300 ml) was fractionated in 
Column 8. From this distillation .there was obtained 226 ml of material 
which "boiled 163.7 to l6U° C (uncorrected).. This product was redis- 
tilled in the same' column, and there was collected 186 ml of constant- 
boiling, constant-refractive- index material. The physical constants of 
this product after filtration through silica gel were: freezing point 
-37.5° C, np 2 ° ■ 1.^361, d 20 = 0.7803, tolling, point 165.5IJ. to I65.56 C 
at 750.5 millimeters of mercury. 

Later, two other methods for the' preparation of this decane were 
investigated. Both of these methods involved the methylation of 2,2,3,U- 
tetramethyl-3-chloropentane. This chloride was prepared in good yield 
from the corresponding alcohol "by reaction with concentrated hydrochloric 
acid. The chloride decomposed easily when a "boiling-point determination 
was attempted at atmospheric pressure. It would not crystallize at dry- 
ice temperature and had an index of refraction np 20 of IA389. The 



30 NACA TN No. 12^7 



carbinol was prepared "by the reaction "between n^thylmagne s^lum "bromide 
and 2,2,^-trimethyl~3-P9ntanone. '..',■'■ '' ; , ...... 

i .• * * t ' ' ,"•? . ' ! ».''■... 

In one experiment (November I9V3) on the me'thylatioh of ttiiB' chlo- 
ride, 1.7 moles of the chloride in 320 ml of "benzene was. added to ,2.5 
moles of dimethyl zinc, using the previously described 'teb^hnigue.. ' .Dis.- 
tillation analysis pf. the- product of reaction shoved' the. presence of 0.,% 
mole (23.5 percent).' .of 2-isbpropyl"-3,'3-dimethyl-i-hutene arid 0»8l mole . ■ 
(47.5 percent) .of 2',3,3,^tetramethyl-l-pehterie, "both' formed by. dehydror 
chlorination of the alky 1. chloride . ' In Mditioh, ' there was found. .38. 
mole (assuming C 10 H 22 ) of material which "boiled 150° to l6o° C, and from 
which no pure material could "be isolated. 

In another experiment (May 19kh) i 10.7 ; moles of '2,2,3, ^-tetramethyl- 
3-chloropontane was treated with 11.0 moles of methylmagne slum ."bromide 
in ether solution. ■ The reactiori waB allowed to 'take ..place . over, a period 
of 3 weeks at 15° to 22° C. ■ The products of the reaction, as determined 
"by distillation analysis, consisted of 3.0 moles (28 percent) of 2-iso- 
propyl-3,3-dimethyl-l-"butene, and 5.7 moles .(53 percent), of 2,3,3,^- 
tetramethyl-l-pentene, formed •"by/dehydrochlorination of the' alkyl chlo- 
ride. In addition, there was found 0.5 mole (h.7 percent) of crude 
2,2, 3, 3,^-pentamethylpentane (158°- to 16*7 P ' C, ■ n^ .* i',fc35^' to' 1 .U369) . 

It is interesting to note that in "both of these trials., the dehydro- 
chlorination of the alkyl' chloride 1 Ted' i;o approximately the same relative 
proportions of the two nonenes) namely, one part of . 2r£sopropyl-3,3- . 
dimethyl~l-"butene,' and;.' two. parts of : 2,3;3^'-tetramethyl-i-'pe'n : tene.. This, 
proportion- is not the same &s occurs when the carbinol'. it self is deny':: 
drated. in that case the. proportions are : three parts of 2-isopropyl-3,3- 
dimethyl-l-"butene and one part of 2,3,3>^-tetramethyl-l-pehiene. ' (See 
reference 15.) 

• Pentamethylpentanes from p^^A^-P'eniamethyi-S-pentanol -'■! ►-' In ,. 
an attempt to prepare, 2,-2,3,4,^petttam£thyipehtane, .it has "been found ' ■ . 
that ,2,2,3., ^., Vpe&teaiie'thyl-S-.p'enitariO'l will dehydrate . under the. .influence - 
of iodine .to. a mixture of .two -decene'sj' which, on hydxogeriatioij, yields 
"both of the. •pe'ntamethyl^pen'tanes; ;'■.■" ''"' : ' ■■"' ' •' ;■'* " . 

$n 1933 Whitmore and Laughlin (reference 17) reported the dehydra- 
tion of 2,2,3,^,U-pentamethyl-3-pentanol "by means of 3 -naphthalene sul- 
fonic, acid to g£vev2rtrhutyl-3>-3*dimethyl-l-hut 

rearrangement. They- also reported a' small amount of low-Trailing, ' uniden- : 
tified. material.' -...-.. , ■ ; ■-..■.-: ■■■?' -•'■' 

...... , i : -I- 1 .. ' ■" ' ■' .' ■ ' 

: ■ . ■ '.,".' ; '' -i ".' - : '■"' ' ■ ' ' ' . . r ., • ■", ■ '■ ■• 

Since this reaction offered a means of preparing 2,2,3,U,^-rp'enta- 
methylpentane t a trial ;"■ 3?un ; was made . • "When'' the' carbinol was' dehydrated 
with p, ^naphthalene sulfonic ac id .>&t'-' atmospheric pressure, 5 the products 
of the reaction consisted of isohutylene, 2,3-dimethyl-l-hutene, 



NACA TN No. 12^7 31 



2,3-dimethyl-2-"butene, and only a small ■ amount, of higher-hoiling material. 
No 3j3-dlmethyl-l-"butene was found In the reaction products. Dehydration 
of the car"binol with iodine was found to' yield- a mixture of decenes, com- 
posed of 2-t-Tratyl-3,3-dimethyl-l-"butene and 2,3,3,li ; ,lt-pentamethyl-l- 
pentene. 

(l ) Preparation of 2 T 2 T U-trimethyl-3"Peatanone and 
2,2,4,^-tetramathyl~3-pentanone 

Preparation of 2,2,*l--trimethyl-3-pentanone was made "by the Haller- 
Bauer synthesis (reference 2k) in toluene solvent "by the action of sodium 
amide and then methyl sulfate on 2,U-dimethyl-3-pentanone. Sodium amide 
was made in 90- to ^-percent yield "by the method described in reference 
25. The crude 2,2,it--trimathyl-3~pentanone was methylated a second time 
"by the same method to give 2,2,k,4-tetranethyl-3-pentanone.. The manipu- 
lative details of these reactions are described "by Whitmore and Laitghlin 
in reference 17 . The over-all yield was 58 percent of that theoretically 
possible, calculated without including recovered 2,lf--dimethyl~3 i -pentanone 
and 2,2,4-trImethyl-3-'pentanoiie, which were recycled in the synthesis. A 
charge of this ketone was fractionated in Column 1, for the isolation of 
a pure sample for physical-constants measurements. In the same column, 
a sample of the 2,2,^,l4--tetramethyl-3-pentanone was also, distilled for 
the, Bame. purpose . 

(2) Preparation of 2,2,3A t ^-psfttamet;h,yl-3-pentanol 

A, solution of 10 moles of methyl magne si urn "bromide was reacted with 
8.75 moles of 2,2,4,^-tetramethyl-3-pentancne and the product worked up 
In the usual manner. Fractionation of the product in Column h at a pres- 
sure of 5? millimeters of mercury gave a forerun of 307 ml of material 
which "boiled "below 105° C . At this point the carMnol "began to solidify 
in the condenser and the pale yellow material remaining in the pot was 
found to "be quite pure carMnol (melting pcl::t ahove 37° C) . A portion 
was recrystallized from ether for use in the determination of physical 
properties . The yield amounted to 75 percent of the. theoretical quantity. 

(3) Dehydration of 2,2,3,U»fr-P6ntamethyl-3-pentanol 
with g -naphthalene sulfonic acid . . 

Dehydration of 897 grams (5.7 moles) of 2,2,3,lj-,^-pentamethyl-3- 
pentanol with 8 grams of 3 -naphthalene sulfonic acid under a fractionat- 
ing column resulted in the distillation of a water layer, an organic 
layer (855 ml), and ahout 50 ml of material collected in a dry- ice trap. 
The organic layer, which smelled strongly of sulfur dioxide and hydrogen 
sulfide, was washed, dried, and distilled from sodium, and gave the fol- 
lowing fractions: 



32 



NACA TN No . 1247 





Boiling range 








Fraction 


(Head temperature) 


Volume 


Refractive .index, 


■_ so 




(°c) 


. "(si) 






1 


5* 


k 






2 


54 to 57 


65 


1.3908 




•3 


51 to 71 


26 


: 1.4033 




k 


71 to 73 


. 23 


I.U084 




5 


73 to. 75 


365 


1.4100 




6 


75 to 150 


35 


■1.4223 




7 


150 to 153.2 


24 . 


•1.4375 . 




8 


153.2 to 156.5 


33 


l.UUoo 




9 


156.5 to 157 


Ik 


. 1.4411 




Residue 


157 


22 







a Dietillation interrupted. 

A considerable quantity of gas was evolved during the- distillation. 
This gas "boiled at a"bout -4° C, was readily absorbed in sulfuric acid, 
and absorbed bromine. Regeneration froc. sulfuric -acid solution by neu- 
tralization resulted in t-butyl alcohol. This identifies tho g.?.s as iso- 
butylene. 1'he other principal products of the reaction were .fraction 
2(2,3-dimethyl-l-butene), fi action 5 (2,3-dimethyl~2-butene), and frac- 
tions 7 and 8, which probably contained a mixture of 2,3,3,4,4-pente'- 
methyl-1-peritene and 2-t-butyl-3,3-dimethyl-l-butene. Since the products 
of this distillation did not yield the desired.' compounds in any appreci- 
able quantity more elaborate analysis was not" undertaken . 

(k) -Dehydration , of 2/2,3,4^4-pentemethyl-3-pentanol 
with id&ine ! , 

■" A charge of 2.2,3,4,4-pentaime'thyl-3n>5r-+8Tiol (640 grems, 4.1 moles) 
was refluxed with 4 grams of iodine and the product distilled through a 
short' fractionating column, yielding 70 ml of water and 700 ml of organic 
material. The organic layer was washed > dried, and fractionated roughly. 
The distillates from three runs were combined, yielding I950 ml of mate- 
rial which, on further fractionation, gave 1800 ml boiling 140° to 155° C. 
The residue was semisolid and had an odor similar to that of a carbinol. 
The 140° to 155° C fraction waa redistilled into the following fractions: 



NACA TN No. 12^7 



33 





Boiling range 






Fraction. 


(Head temperature) 


Volume 


Refractive index, n D ao 




(°c) 


(ml) 


(uncorrected) 


1 


100 to 1W.2 


55 


1.1I-31U 


2 


2A8.2 to 1^9.0 


^3 


l.lf-3^8.. 


3 


1^9*0 to lk-9,6 


283 


1^355 ■■■■■ 


k 


149.6" to 151.0 


U6b 


1A355 ;:■ ■ 


5 


151.0 to 152.0 


190 


1.A367 - ■ ■ 


6 


152 e0 to 153.0 


55 


1A3S1 ... 


7 


153.0 to 155.0 


50 


1.^39$ -.-■ ■ 


8 


155.0 to 157.0 


26 


l.¥HQ ,-. 



A constant-hoiling portion of fraction 3 was reserved for determi- 
nation of physical constants and ozonoiysis . At 157° G, solid .material 
started to form in the condenser; so the distillation was stopped. The 
cooled residue in the flask was solid, melting at 3^.5° to :37«5° C-, "but. 
a mixture of this compound and the original carbinol was liquid at room 
temperature. The material was soluble in ether, insoluble, in water, 
slightly soluble in 85-percent phosphoric acid and was . unaffected "by 
sodium. 

Analysis showed the presence of 83 .1 percent .carbon and 13.8 per-' 
cent hydrogen. Because of the volatility of' the compound, these results 
Stty bo low. By extending the CH content to total 100 percent, the anal- 
ysis was calculated to 85.8 percent carbon and 111-. 2 percent hydrogen, 
which agrees with the analysis' of an alkene. The molecular weight was 
found cryoscopically to "be lU2.k (theory for 



c ioSbo'- lk0 ' 1 ^ 



At this point the distillation of the solid olefin was continued 
after -provision had "been -made to. prevent solidification of material, in 
the .condenser.- This distillation gave the following fractions 1 • ■• 





Boiling range 




Fraction 


(Head temperature) 


. Weight 




(°c) 


' (grains) 


■ 9 


157.0 to 157.2 ■ 


' :30.1 


10. 


157.2 to 158.0- 


• 18,6 


11 


158.0 to 158.2 


18.1). 


12 


158.2 to 158.2 


27.7 


13 


158.2 to 158.9 


28.1 


ik 


I58.9 to 159.0 


28.3 


15 


159.0 to 159.0 


28.2 


Residue 




39.1 



Ozonolysis was performed on fraction 15. 



3^ NACA TN No . 12^7 

(5) Ozonolysie of Alkenes 

(a) Lover-"boiling alkene (2-t-T3utyl-3,3-dimethyl-l- ' 
"butene) 

Ozonlzation of 0.21 mole of alkene in 300 ml isopentane at ~5° to 
-10° C was accomplished in 12 heirs. Oxygen containing 7.5 percent ozone 
was used at the rate of 7500 ml per hour. The solvent was not removed 
prior to decomposition, "because the ozonide proved 'to "be a solid. Decom- 
position was effected "by means of the technique developed "by Whitmore and 
Church in reference 26 » The reaction was of medium violence and gave 
rise to 36.5 ml of oil and 150 ml of water layer. Analysis of .the water 
layer showed the presence of 0.18 mole of formaldehyde and no other low- 
molecular-weight aldehyde or ketone. The oil was distilled to yield 
2U.3 ml of 2,2,^,4-tetramethyl-3-pentanone ("b.p. 150° to 155° C), which, 
when treated with methylmagae si urn "bromide, gave 2,2,3,U,^-pentamethyi-"3- 
pentanol, the identity of which was proved "by a mixed melting point with 
a known sample . 

(Td) Eigher-"boiling alkene (2,3,3,^,l+-pentamothyl-l- 
pentene) 

Tn the same manner as described, 0,11 mole of the higher-boiling 
alkene was ozonized in 300 ml of isopentane at -10° to -20° C to yiold 
0.071 mole of -formaldehyde and 9 grams of an oil. ("b.p. 172° C, 
nj) 24 ss 1 .it-lM?) . This oil gave a positive iodoform test, and • was oxidized 
"by 50 -percent nitric acid to 2,2,^,3-tetra^ethyl'butanoic acid. (See ref- 
erences 27 and 28.) After sevoral crystallizations from alcohol, this 
acid melted at- I96 to 197° 0, the same value repdrted in reference 29. 
The neutral equivalent was found to "be 1^7-3 • The amide was prepared and 
found to melt at 201.5° to 202<,2° C, which agrees with the melting point 
(201° to 202° C) found in reference 29. The ketone gave a 2,l|-d:!nitro- 
phsnylhySrasone which melted at 182° to 183° C . The ketone was therefore 
considered to "be 3,3,^,4-tetrejaethyl-2-pentaiione. (Analysis: IT found^ 
17.20, 17.28 percent,* calculated for CisHgaBf/iOej 17-27 percent.) 

■■ (6) Hydrogenatiori of thedeceries 

The crude lower-"boiiing alkene from the dehydration of 2, 2, 3,1+, h- 
pentaifl.ethyl-3-pentanol (fractions 2 to 8) was hydrogenated and filtered 
through silica gel. Distillation in Column 5 gave: 



NACA TN Ho. 1247 



35 



Fraction 


Boiling range 
• (Head temper attire) 

(°c) 


Volume 
(b1) 


Refractive index, ;• n^ 


1 to 2 
3 to 8 
9 to 14 
15 to 16 
Residue 


153.4 to 158.4 

158.4 
158.4 to 159.8 
. 159.2 to 161.7 


lOO' 
. 300 

303. 

. 97 

47 


I.4296 to 1.4304 

. 1.4306 to" 1.4307 . 

1.4307 to 1.4313 

1.4320 to '1.4341 

I.4360 



An analysis of the distillation curve showed the presence of 735 ml of 
2,2,3,4,4-pentamethylpentane and 112 ml of 2,2,3,3;4-pentamethylpentane.. 

Hydrogenation of the higher-foiling ■ alkene was carried out 'in- a' ' 
solvent (2,2,4-trimethylpentane) .. Distillation gave, in addition to the 
solvent, a small forerun, and 247 ml effractions collected at 163 to . = '■_ 
164° C (np 20 » 1.4358 to I.4361). The test: samples of "both decanes were: 
reserved for measurement of physical constants. " : " • '■ ; 

The yield of alkanes isolated in the.' pure state (calculated on "■' 
2,2,4,4-tetramethyl-3-pentanone) amounted to 25.8 percent: of 2,2,3,4,4- 
pentamethylpentane and .11.4 percent of 2,2,3,3,4- : peritamethyiperitane. . 
These yields could' not T>e used to form a definite" 'opinion of the reac- ' 
tion, nor can much weight "be placed .on the ratio of 'products found, 
since a loss experienced in the distillation and handling of the higher 
■boiling decene is not accounted fori _-■"■ 

Fentamethylpentanes from ."2, ; 2 t -3,4,4-pentamethyl-3-peri-6anol'- IX »- ■ 
The second run of this series of reactions was made' to increase -the ■'■■ 
stock of hydrocarbons and to obtain more' information -on the ratio of ' 
products formed "by dehydration 'of the carhinbl. ■ •'■ : " 

: Cl) .Preparation ! 'of :2,g,4--trimethyl-3-pentaribne ' 



For this' second 'synthesis,- "an easier method was' devised for making 
2,2,4-trimethyl-3-.pent'anone. ThiB "method ■■was "an" adaptation of that de- ' 
scrihed: "by Nef- in reference '30 vhb obtained ' this 'ketbn'e "by the -Exhaustive 
methylation of acetone, methylisopropyl ketone, diethyl ketbrie, or 
pinacolono with methyl iodide and potassium hydroxide in a sealed tube 
at l40° C. The-method used in' the. present ..work" euhTstittit'ed.; the less ex- 
pensive methyl "bromide for methyl iodide in the methylation of commercial 
2-,4-dimethyl-3^pentanone. " ■ ? .'.•■'. ■•:.•'... "' . .-.■-■ '.■■"■■■ ' ' ' * '•■■'•'■' 

• Several .runs of various ''sizes were 1 made 1 and" the results are 'sum- 
marized in -the fdllowirig- ta"ble: >■■.-- 1 ;■'.;■ ■■; .- + ■ • '1-': .■■■;,'. 



36 



NACA TN No. 121+7 



METHYLATION OF 2,U-DIMElTHYL-3- : PE3STAT5rOKE 



( 










Yield of 2,2,1+- 


Methylatlng 

agent 

(moles) 


2, ^-Dimethyl- 
s-pent anone 
(moles) 


Potassium 

hydroxide 

(moles) 


Temperature 

(°c) 


Duration 
(Br) 


trimethyl-3- 
pentanone x 
(percent) 


CH 3 I (1.5) 


1.2 


3.5 


ll+O.to l60 


7-0 


55 


(CH 3 )^50 4 (1.5) 


1.2 


■ 3-5 


ll+Q. to 160 


7.2 





CH^Br (1+) '." 


k 


IS 


160 to 170 


6.0 


35 


CHsBr (k) 


k 


12 


ll+O to 150 


9.1 


15 


CH 3 Br (1+) 


k 


12 


190 to 200 


■ 11.7 


35, 


CE 3 Br (1+) ' 


h ,. 


6(CaO) 


190 to 200 


8.0 





CHsBr (1+7.7) 


. 39.6 


120 


200 to 215 


.8.0 


57 


CH 3 Br (U7.7) 


39.6 


120 


19P, to 200' 


10.0 


51+ 


CH 3 Br (1+7.7) 


39.6 


120 


200 to 230 


8.0 


.1+7 



''Based on 2,l+-dimethyl-3-pentanone consumed. 

These reactions were carried out in hydrogenatipn' "bombs. The "bomb 
was chilled "by Bolid carton dioxide and charged with the. reactants, then' 
sealed and heated to the temperature indicated. 'Since the reaction. is 
exothermic, it was "found difficult to hold a predetermined narrow temper- 
ature range. (The operation could probably "be made, more efficient "by 
pumping the methyl- "bromide into the reaction vessel as it is consumed "by 
the reaction in order.. to obtain more sta^e reaction conditions.) When 
the reaction wds complete the bomb was copied and the contents washed 
•well with watery dried, and fractionated. In 'one experiment an attempt 
was made to distill the residue (2l+7 grams) . It was found to contain 
lachrymatory-materials., "but little, if any,' 2,2,lfc,l+-t6tramethyr-3- 
pentanone. None of this compound was found "by Nof in any. of his methyla- 
tion products. 

* ' ■■..-.. 
(2) Preparation of g^.l+^-tetramethyl-S-pentanone 

r 

While tho preparation of 2,2,l+-trimethyl-3-P©ntsnone was in progress, 
a now and simpler method for synthesizing 2,2,l+,l+-tetramethyl-3-pentanone 
was described "by Bartlett and Schneider, (See reference 23.) This new 
procedure eliminated entirely the necessity of using sodium amide in the 



NACA TIT No . 12^7 37 



synthesis • The Bartlett and Schneider reaction involved Interaction "be- 
tween t-.butyl chloride, methyl, trimethylacetate A and sodium sand to give 
a mixture of 2,2,^,lj;-tetramethyl-3-pentanQne/ and: 2,2, i f-,lv-tetramethyl-3 
pentanol. as. major products. _ ■" 

Several small-scale runs (1.6 to 2.0 moles) of this reaction were " 
made. There was no appreciable difference in the yields of di tertiary- 
"butyl, compounds from reactions In which •technical isooctane (2,2,l; : - 
trimethylpentane) was used as a solvent and those in which isopentane 
was used. Since the former solvent is considered safer, it was used in 
the majority of the trial runs and In the large-scale run. Slightly 
larger (2 to 5 percent}' yields were chtained "when sodium sand was used 
rather than Bodium wire'. In none of the small-scale runs did the yield 
of- combined di tertiary-butyl compounds 'exceed 53 percent. (Bartlett 
and Schneider report yielde up to 71 percent.) ' After the technique for 
handling this roaction had been sufficiently developed, a large run was 
made in the stainless-steel kettle.' 

(a) Methyl trimethylacetate 

To a solution of 53 kilograms (177 moles) of sodium dichromate di- 
hydrate (technical) in 98 liters of water in the glass-lined reactor was 
added 39.9 litors of concentrated sulfuric acid. The' solution was heated 
to 82° C and 6.6 kilograms (59 moles) of 2,^,4-trimethyl-2-pcntene (97 
percent pure) was added over a period of 5 hours. The rate of addition 
was regulated so that the temperature of . the' mixture did not exceed 88° C. 
Thon about 3 liters of methyl alcohol was added to use the excess dichro- 
mate, .and the mixture was subjected to steam distillation. There" were - 
obtained 5*76 kilograms of organic layer and about 36 liters of aqueous 
layer. The aqueous layer yielded, on distillation, an additional 0.82 
kilogram of organic material. The crude product was distilled In ColV • 
uinns k and 5, and yielded 3.91 kilograms of trimethyl acetic acid' (b.p. 
l6o° to I65 C) 65.O percent yield). The methyl ester of trimethylacetic 
acid was prepared In the usual manner by' refluxlng a solution of the' 
acid in methyl alcohol. Sulfuric acid was used as the catalyst. 

(b) 2,2,|t,J<-Tetramothyr-3-pentanone ' 

Sodium sand, from 6.8 kilograms (300 moles) of sodium was prepared 
under toluene (22 liters) in the usual manner. The mixture was cooled 
to 15° C and 16 liters of technical Isooctane (2,2,l*-trimethylpentane) 
and 16 kilograms (173 moles) of t-butyl' chloride were added. ■ After the 
reaction was Initiated by the addition of a small quantity of ester, the 
remainder (total 7«98 kg, 68.5 -moles) was added during % hours, whilo 

'the temperature was maintained at 35 to- 1*0° C . Stirring was continued 
for 8 hours, then the mixture was allowed to stand overnight . The- prod- 

' uct was worked up in the manner described by Bartlett and- Schneider in 
reference 23. Distillation -gave 2.57 kilograms (18.1 moles) of-'2y2,l*-,^.- 



•38 NAG A TN No. 12^7 

tetramethyl-3-pentanone (b.p. 151.5° to I56.O C), 666 grams of Inter- 
mediate, .and 2 .72 'kilograms (18,9 moles) of 2,2,4,k-tetrametbyl-3-pentanol 
("b,p. 167° to 173° C).. Including the intermediate, this represents a 
yield of approximately 6l percent, "based on methyl trimethylacetate . 

. The carMnol fraction and the intermediate containing carbinol were 
combined and oxidized in two batches. In each batch I.36 kilograms' 
(9A5 moles) of carbinol and 333 grams of intermediate were suspended in 
a solution of 1255 grams of sodium dichromate dihydrate in 1170 ml of 
water. ■ While the reaction mixture was held at h5° to 60° C, a solution 
of 2300 ml concentrated sulfuric acid in 2170 ml o'f water was added dur- 
ing 2 days, after which the reaction mixture was stirred and heated to 
50° C for 1 day. The organic material was then steam distilled, dried, 
and fractionated. There was obtained 1.35 kilograms (9*52 moles) of 
ketone (b.p. 151° to 15^° C; 78 percent yield). 

In the same manner, all the 2,2,l}-,U-tetramethyl-3-pentanol obtained 
in the several preliminary runs was oxidized to ketone, and all the 
ketone from the several sources, was combined. This included a small 
amount prepared by the Haller-Bauer reaction. (See reference 2k.) 

(c) Preparation and dehydration of 2,2, 3, 4, it- 
pent amethy 1-3 -pent anol 

The 'pentamethylpentanol was prepared in the manner already described. 
Prom 6i$6 kilograms (U9.C moles) of 2,2.Uj^-tetramethyl-3-pentanone there 
was obtained k.8k kilograms (30.6 moles) of 2,2,3, k,k- pentamethyl~3-pentanol 
(62.6 percent yield). Dehydration of the carbinol was caused by refluxing 
with iodine.' In a trial run, 332 grams (I.98 moles) of carbinol was 
boiled with 3.3 grams cf' iodine. During 2 hours, 93 percent of the theo- 
retical quantity o:C water was eliminated and collected. The organic layer 
was washed with sodium, thiosuifate solution and with water, dried, and 
distilled in OoIigki 17 . The charge was 2^6 grams. The decene fractions 
(b.p. 1^5° to 158,9° C) weighed 216.6 grams (1.5^ molesj 78 percent) . 
Analysis of the distillation' curve shewed that these fractions consisted 
of equal parts of the two isomers, 3,3,-dimethyl-2-t-butyl-l-butene and 
2,3,3, i 4-,U-pentamethyl-l-pentene. Treatment of the main portion cf the 
carbinol for the preparation of the pentamethylpentanes followed the pro- 
cedure already described. ■ : ' 

2,2,5,5-Tetramethylhexane and 2,2,U,5-Tetramethylhexane 

The synthesis of 2,2,5,5- and 2,2,lf-,5-tetramethylhexanes was accom- ' . 
plished by the following reactions: (a) oxidation of 2,l*,^-trimethyl-l- ,. 
pentene to ^,lf--dimethyl-2-pentanone (methyl neopentyl ketone), (b) oxida- 
tion of this ketone to t-butylacetic acid, (c) conversion, of the acid to 
methyl. t-butylacetate, :(d) -reaction of the ester with "Vbufylinrigneslum .. 



MCA TN No. 12^7 39 

ohlorlde to give 2,2,5,5-tetramethyl-3-boxanol, (e) dehydration of the 
carbinol to a mixture of 2,2,5,5-tetramethyl-3-hexone, 2,3,5,5-tetra- 
methyl-2-hexene, and 2,3,5,5-tetramethyl-l-hexene, and (f) hydrogenation 
of the first-named alkene to 2,2,5,5-tetramethylhexane and of the last 
two alkenes to 2,2,11-,5-tetramethylhexane., 

Oxidation of 2A.^-trimethyl-l--pentene ,- The' oxidation of 2,k,k- 
trimethyl-1-pentene was carried out essentially in the manner disclosed 
by Whitmore, Hameyer, and Trent- in reference 15 . Several runs were made 
using olefin of 95-percent or higher purity. (The isolation of this 
olefin is described later.) In a typical run, 101 moles of alkene was 
oxidized during 10 days with sodium dichromate "by the slow addition of 
sulfuric acid. There were obtained 1800 grams of acidic material and 
.9360 ml of neutral oil which, upon distillation in Column 3', gave 215lj- 
ml of forerun, if-150 grams (3&A moles) ^lt-dimethyl-2-pentanone (b.pv 
123° to 126° C), and 2000 ml of residue. This yield of ketone is equiv- 
alent to 36 percent of the theoretical amount. The aoidic material was 
found to "be a complex mixture containing only minor quantities of tri- 
methylacetic and t-butylacetic acid,, and was not further investigated. 

Oxidation of . methylneopentyl ketone .- The hypohalite oxidation of 
the methylneopentyl ketone to t-butylacetic aoid was accomplished -"by a 
modification of the reaction disclosed in reference 15. There sodium-" 
hypobromite (prepared from bromine and sodium hydroxide) was used,, while 
in the present work ! the- less expensive, commercially available calcium ■ 
hypochlorite was used. Several small preliminary runs were made to " 
develop familiarity with th& reaction "before a large run was undertaken. 
Three- large runs- were made, ono of which is_ described. 

-■ A' solution- of 1^.0 kilograms of technical sodium' hydroxide in 38 
liters' of water was prepared. This .solution was cooled to 19° C.and to 
it were added .about 90 kilograms of cracked ice and 13 kilograms of. com- 
mercial calcium hypochlorite (70 -percent chlorine). The temperature 
thereby obtained was about -k° C. The ketone (50 moles) was then added 
during 3' hours. The temperature of the reaction mixture remained below 
+5° C during this addition. An additional 25 kilograms of cracked ice 
was added and the mixture stirred for 10 hours, after which it was 
heated to '6*5° to 70° C for 5 hours. After cooling the mixture to 20° C, 
I9.7 liters 'of sulfuric acid was added slowly and the products steam ' 
distilled. The crude product' was distilled in several batches from a 
1-liter Claison flask.- There was obtained U070' grams (31 .3 moles; 63 -' 
percent) of acid collected between 180° and I9O C. No further purifi- 
cation of the acid was made. > 

Conversion of t-butylaoetic acid. to methyl t-butylaoetate .- The. 
methyl ester of t-butylacetic .%ac id was made in the orthodox manner.- In 
a typical run .a solution of ItlUO grams (35*7 moles)- of. acid and 300 ml 
of concentrated sulfuric acid in 10 liters (250 moles), of methanol was 



kO NACA TN No. 121+7 



heated to reflux for two periods of 7 hours each. The crude product ob- 
tained was' distilled in Column 5 and gave 3560 grams (27 ,k moles ; 76.7 
percent) of ester, which was collected at 125° to 127° C. 

Preparation of 2 » 5 , p , 5-tetramethyl-3-hexanol . - The preparation of 
2,2,5,5~tetramethyl-3-hoxanol was carried out by the use of the reaction 
described by Moersch (reference 31) which is an adaptation of that used 
by Heyd (referenoe 32}. 

To the ■ G-rignard reagent prepared from 326 gram atoms of magnesium 
and 32'S moles of t-butyl chloride, there was added 6815 grams (52 .k 
moles) of methyl t-butylacetate during 8 hours. The reaction mixture 
was refluxed 7 hours each day for 3 days and allowed to stand each night. 
Decomposition was caused by dilate- sulfuric acid (17 kg concentrated 
acid and 20 kg water and ice). The' product was steam distilled, and the 
aqueous layer extracted with ether. The organic layers were combined 
and the ether removed in Column- 11. The residue was redistilled in Col- 
umns 2*4- and 7, yielding 6507 grams of carbinol collected at 166° to 
170° C- This' is equivalent to Ul .2' moles or 79 percont yield. Moersch 
reported 85 percent yield (reference 31) • 

Dehydration of 2 , 2 , 5 , 5 - tetramethyl- 3-hexanol . - Three preliminary 
experiments were made on the dehydration of this carbinol and on the re- 
arrangement of the resulting olefins. In one run> 117 grams (0.70 mole) 
of carbinol was passed over 256 grams (330 ml) of alumina (Baker Hydralo, 
lot 919^2) at 300° to' 305° C at the rate of kj grams per hour. The cat- 
alyst tube was '2.5 centimeters in diameter. The water recovered amounted 
to 10.8 ml (0.6 mole; 86 percent). The product was dried and fraction- 
ated in Column 17. The yield of decenes amounted to 70 percent (78 per- 
cent on basis of carbinol consumed), and consisted of 3^.5 mole percont 
2,2,5,5-tetramethyl-3-hexene, 35*2 percent 2,3,5,5-tetramethyl-l-hexene, 
and 30.2 percent 2,3,5,5-tetramethyl-2-hexene. 

In another experiment, 118 grams of carbinol was dehydrated under 
the same conditions, except" that the rate was 98 grams per hour. In 
this ca3e, a yield of k6 percent olefins "(73 percent on basis of carbinol 
consumed) was obtained. The mixture of olefins contained 3^.8 percent 
2,2,5,5-tetramethyl-3-hoxene, 1*2.0 percent •2,3,5,5-tetramethyl-l-hexene, 
and 23.2 percent 2,3,5,5-tetramethyl-2-hexene. 

To determine the extent of rearrangement of the 'olefins, a mixture 
of decenes was passed over the catalyst at 300° to 310° C at the rate of 
kk grams per hour. Analysis of the resultant mixture showed that the 
original mixture was isomerized as follows: 2,2,5,5-tetramethyl-3~hexene; 
from 13.5 percent to 16.8 percent; 2,3,5,5-tetramethyl-l-hexene; from 
h6.2 percent to 31.2 percent; 2, 3, 5 ^- tetramethyl- 2- hexene, from Ij-0.0 
percent to 52.0 percent. ■ \ ■ 



NACA TO No. 12l;7 'H 

The bulk of the carbinol vas dehydrated in the manner used in the 
first experiment. The resultant mixture vas dried and distilled in Col- 
umn 5. The carbinol recovered vas recycled for dehydration. In this 
vay, U999 grams of crude olefin mixture vas obtained (86.6 percent yield). 
This mixture vas separated roughly in Column 5 into concentrates "boiling 
121° to 127° C, 139° to IU5 C, and 152° to 158° C, and intermediate 
fractions. A sample (500 ml) of each hydrocarbon vas redistilled in Col- 
umn 17 for preparation of pure compounds. The impure fractions from each 
of these distillations vere returned to the appropriate concentrate. 
These olefins have "been identified previously. (See references 31 and 32.)' 

Hydrogenation .- Each of the olefin concentrates vas hydrogenated 
separately, as vas the combined intermediate. The last tvo olefin con- 
centrates gave the same paraffin and vere combined for distillation. 
Purification of both paraffins vas accomplished in Column 18. The best 
500 ml samples from each distillation vere redistilled in Column 17, and 
physical constants vere measured on the best samples from these distilla- 
tions. 



2, 2, 3, 3-Tetramethylhexane ' 

This hydrocarbon, vhich vas synthesized at Pennsylvania State College, 
vas purified in these laboratories. When received, the sample (2 gal) 
contained chlorides vhich vere removed by boiling vith alcoholic alkali. 
The product vas vashed, dried, and ' fractionated in Columns 19 and 20. The 
best portion from one of- these distillations vas refractioriated in Column 
17. Physical constants vere ■ determined on the best fractions from this 
distillation. 

1 

*3,3,^, 1 <--Tetramethylhexane ■■' 

The method of preparation of this decane is similar to that used in 
the preparation of 2,2,3,3-tetramethylpentane, and involved the reaction 
between ethylmagnesium chloride and 2,3,3-trimethyl-2-chloropentane. 

In the exploratory synthesis. 2,3,3-trimethyl-l-pentene (b.p. 108.3l<- 
to 108. k0° C, n D 2 ° «s l.lt-170 to I.U172) vas converted to the chloride, 
2,3,3-trimethyl-2-chloropentane, by reaction vith dry hydrogen chloride 
at -30° C. The product vas fractionated in Column k. The forerun of un- 
changed olefin vas used in the preparation of more chloride. The chloride 
used in the coupling reaction vas that oollected betveen 8l° and 82° C at 
57 millimeters of mercury. 

To the Grignard solution prepared from 10 gram atoms of magnesium 
and 10 moles of ethyl bromide, there vas. added,- during 7 days, 9.3 moles 
(1382 grams) of the chloride. On the twelfth day the mixture was vorked 
up. The ether vas removed from the organic layer and the residue refluxed 
6 hours vith alcoholic alkali (10 percent KDH) to remove chlorides. ■ The 



42 NACA TN No. 12^7 

washed, dried, chloride-free material was distilled in Column 17 . A 
large run of the preparation of this hydrocarbon is in progress, From 
this run a considerably purer compound is expected. 

2,3-Dimethyl-l-Butene and 2,3-Dimethyl-2-Butene 

The preparation and properties of 2,3-dimethyl-2-butene and 2,3- 
dimethyl-.l-butene have "been reported previously in reference 5. While 
the 2,3-dimethyl-l-butene reported was relatively pure, the 2,3-dimethyl- 
2-butene was decidedly impure. The "boiling range of the best sample of 
the latter was about 0.k° C, even after repeated fractionation} whereas 
other hydrocarbons prepared and reported in the same paper had boiling 
ranges of less than 0.01° C. The wide boiling range has been attributed 
to the presence of peroxides in the sample. This tendency to form perox- 
ides is much more pronounced in the 2,3-dimethyl-2-butene than in the 
one isomer. Since both alkenes result from the same reaction, the study 
of both compounds was repeated. The method of preparing the alkenes was 
dehydration of 2,3-dimethyl-2-butanol by means of iodine. The carbinol 
was prepared by action of methyl magnesium bromide on methyl isobutyrate. 

Several batches of methyl isobutyrate were made, in each of which 
90 moles of methanol and 30 moles of isobutyric acid were refluxed for 
6 to 8 hours with 15 ml of concentrated sulfuric acid. The product was 
recovered by adding water, extracting the unchanged acid by sodium car- 
bonate solution, and saturating the aqueous layer with salt to recover 
unused alcohol and dissolved ester. The combined, nonacidic organic 
layer was distilled in Columns 3, h, 5, and 6. Only constant-boiling 
(±0.1° C) material, was reserved for subsequent steps. The yield amounted 
to 71 percent of the theoretical based on original isobutyric acid. 

In a typical run of the preparation of 2, 3-dimethyl-2-butanol k2 
moles of methyl isobutyrate was added to 90 moles of methylmagnesium bro- 
mide in 12 hours. After the reaction mixture had been allowed to stand 
for 15 hours, it was warmed for h hours and then treated with ice and 
dilute hydrochloric acid. The organic material was dried and distilled 
in Column 6. After ether and unchanged ester had been removed, tho car- 
binol was distilled at j6.k° to 76.6° C at 152 millimeters of mercury. 
The yield *ras 3120 grams (73 percent, based on ester) . 

The dehydration of 2,3-dimethyl-2-butanol was accomplished by heat- 
ing it with 1 gram of iodine per liter of carbinol. The olefinic mate- 
rial thereby obtained was roughly separated in Column h and consisted of 
approximately three parts of 2,3-dimethyl-2-butene and one part of 2,3- 
dimethyl-2-butone . The residue from' this distillation consisted of un- 
changed carbinol which had steam distilled during the dehydration step. 
This carbinol was returned to the dehydration process as it accvmulated . 
In this way, a practically quantitative yield of alkeneB was obtained. 



KACA TU No . 12V7 I4-3 



Two charges of crude 2, 3-dimethyl-2-butene were fractionated in Col- 
umn 1. The middle cuts from these distillations, the fractions of which 
had a constant refractive index (±0.00005), were combined, and amounted 
to 3.6 liters of material. The 2, 3~dimethyl-l-butene was fractionated in 
like manner, and 3.5 liters of material was obtained. The two hydrocar- 
bons were then subjected to distillation in Column 5 under conditions de- 
signed to destroy any peroxides present and to prevent their formation in 
the distillate. This was accomplished by adding hydro^uinone to the dis- 
tillation charge and by keeping the column, take-off, and delivery systems 
flushed with nitrogen. In this way, thirty-three 100-ml fractions of each 
hydrocarbon were obtained. 

For measuring the physical properties of these olefins the same appa- 
ratus and methods previously described were used, but care was exercised 
to displace air in the apparatus with nitrogen during the determinations. 
Refractive indices were measured in the usual manner. Peroxide numbers 
(moles of active oxygen in 1000 liters of solution) were determined by 
the method of Yule and Wilson (reference 33) . 

For 2,3-dimethyl-l-butene, fraction 17 was used for determination of 
refractive index and density. Tho peroxide number of this fraction was 
0.03. Measurements of boiling points of this olefin were made with frac- 
tions 16 and 19. The distillate from these determinations contained an 
unmeasurably small amount of peroxide. The freezing point of ii.3- 
dimethyl-2-butene was made on fraction 17 (0 .07 peroxide number) . 
Refractive-index and density measurements were made on fraction 21 (0.03 
peroxide number), and boiling-point measurements on fractions 18, 19, and 
20 (O.Olj- to 0.06" peroxide number). The measured values of the properties 
are given in table 2. 

Considerable difference of opinion exists regarding the freezing 
point of 2.3-dimethyl-l-butene. Schurman and Boord (reference 3k) report 
a "melting . point of -120° to -123° C on material having a boiling range 
of 0.U° C. Brooks, Howard, and Crafton (reference 5) report a freezing 
point of -1^0 .1° C on. a sample of high purity which, however, undoubtedly 
contained some peroxide. Kistiakowsky and. coworkers (reference 35), 
using a sample having a boiling range of .01° C for use in determining 
the heat of hydrogenation, ' reported that the material congealed to a glass 
at low temperatures. Two attompts were made in this work to freeze sam- 
ples which were peroxide-free, but. both were unsuccessful. An attempt to 
freeze samples recovered from the boiling-point distillates, which had 
been exposed to air for 2 weeks also failed. Attempts were made to freeze 
samples containing small amounts of 2,2,l+-trimethylpentane,- those samples 
containing O.58 and 2\k mole percent of this impurity -failed to freeze. 
One sample containing I.U3 mole percent 2,2,^-trimethylpentane gave an 
indefinite freezing point at -llj-5.lt- C. This value seems to substantiate 
the previous value of -mo.l C (reference 5) and would indicate a very 
low heat of fusion, which may be a controlling factor in the determination 
of the freezing point. 



kk NACA TN No. 12V7 



The presence of peroxides caused a marked change in the boiling 
ranges of these olefins. When samples of pure 2,3-dimethyl-l-butene 
were distilled in the 'boiling-point apparatus, the observed temperature 
changes (from 20 to 80 percent distilled) were less than 0.00V 3 C. The 
same material, after exposure to air for 2 months showed a distillation 
range (20 to 80 percent) of 0,11° C. Still more pronounced is the effect 
of peroxides on 2, 3 -dime thy 1-2 -"but ene. Samples containing a smell quan- 
tity of peroxide (peroxide number 0.0*0 distilled over a rango of 
0.007° C or less, "but after this material had accumulated peroxides for 
10 days the distillation range was found to "be 1.03° C. 

In order to determine the .rate of peroxide formation under normal 
laboratory conditions, samples of purified alkenes were allowed to stand 
at room temperature in contact with air. Periodically, portions were 
withdrawn ■ and analyzed for peroxides. The results of these analyses are 
given in figures 3 and k. The great difference in rates of peroxide for- 
mation in the two compounds may "be seen in. the comparison given in fig- 
ure 3. 

3-Methyl-2-Pentene (cis and trans) 

The two geometric isomers of 3-methyl-2-pentene were prepared by 
dehydration of 3-methyl-3-pentanol, which was formed by action of ethyl - 
magnesium' chloride on 2-butanone . 

To 53.8 moles of ethylmagnesium chloride was added 55.8 moles of 2- 
butanone in 5 liters of ether. The yield of carbinol (b.p. 75° to 80° C 
at ll)-2 mm Hg) was ko percent of the theoretical. The carbinol was dehy- 
drated with p -naphthalene sulfonic .acid to yield a mixture of olefins. A 
charge of 22*40 ml of the washed, dried olefin mixture was fractionated in 
Column 2, which gave 2U0 ml of the .lower-boiling (cis ?) and 96O ml of the 
higher -boiling (trans?) Isomers. Physical constants were measured on the 
best samples of each isomer. Analysis of the distillation curve showed 
that the original mixture contained 9.6 percent (by volume) of tho lowor- 
boiling and T^+ percent of the higher-boiling forms. 

The identification of these two olefins as cis and trans 3-methyl- 
2-pentene, rather than the isomers 3-methyl-2-pentene and 2-ethyl-l- 
butene, is based primarily on mass spectrometer studies. The two pat- 
terns formed by analysis of the compounds obtained ar^ very nearly iden- 
tical. No third component was isolated from the distillation, although 
it is probable that one was present in small quantity. 

Investigation of Diisobutylene 

It was neoessary to isolate large quantities' of the two diisobutyl- 
enos, 2,U,l|-trimethyl-l-penteno and 2,l)-,ij--trimethyl-2-pentene, in order 
to provide samples for engine ■ studies and for the syntheses of k,h- 



NACA TN No. 12^7 ^5 

dimethyl-2-pentanone and trimethylacetic acid - "by oxidation. For this 
purpose, a considerable quantity (kJO liters) of the commercial mixture 
was systematically fractionated* 

The original material was separated into five "cuts" or concentrates 
by fractionation in Column 11. Because of the limited pot capacity, it 
was necessary to perform this operation in "batches. Corresponding cuts 
from each batch were combined. The data on these distillations are sum- 
marized in table k» 

Cut A (forerun) comprised an azeotrope containing a small quantity 
of 2,i-Jj--trimethyl-l-pentene with butyl alcohol, along with other polar 
compounds. This cut was not extensively investigated. 

Cut C (58 liters), the intermediate between cuts B and D, was re- 
fractionated in Column 11 to yield 3h liters of 2,k,i(-trimethyl-l-pentene 
which was combined with cut B, Ik liters of intermediate which was not 
further investigated, and 9 liters of residue which was added to cut D. 
The augmented cuts B and D were then designated as Brl, and D-l, respec- 
tively. 

Cut B-l (298 liters) was found to be about 96.7 percent pure Q,k,k- 
trimethyl-1-pentene,- its freezing point was -96. 5° Co A 170-liter por- 
tion from the middle of this cut was refractionated in three runs and 72 
liters of purified 2,i,l»-trimethyl-l-pentene was obtained, comprising 
fractions with freezing points in the range -93 .59° to -93^55° C. 
Physical constants were measured on one of the fractions of -93-55° C 
material. These constants agree with those reported by Tongberg, 
Pickens, Fenske, and Whitmore (reference 36) . This compound has been 
identified by ozonolysis by Whitmore and Church (reference 26) . 

Cut D-l (95 liters), a concentrate of 2,^,l(-trimethyl-2-pentene, 
was refractionated in two runs. From these distillations, there was ob- 
tained U9.3 liters of high purity 2,lt-,lj--trimethyl-2-pentene, composed of 
fractions with freezing points from -106.62° to -IO6.58 C. A portion 
was refractionated in- Column 1 for isolation of a sample for physical- 
constants measurements. This compound was also characterized by Tongberg 
and others (reference 36), and identified by Whitmore and Church (refer- 
ence 26) . 

The residue from distillation of cut D-l was 'fractionated in Col- ■ 
umn 1. From this distillation there were obtained two concentrates, 
designated as D-2 and D-3. 

Cut D-2 (7^5 ml, b.p. 106.8° C, n D eo = Lklkg to 1.U152, 
d = O.7265) was probably an impure sample of 2,3,U-trimethyl-l-pentene. 
Kuykendall (reference 37) obtained the. following properties for this 
compound: b.p. 106.7° to 107.7° C, n^ 20 = i.klk6, d 2 ° = O.726. 



h6 NACA TW No. 12^7 

Cut D-3 (Sok ml, "b.p. 108.0° c, n^ 20 = l.kl62 to 1.1*171, d 2 ° » 0.733) 
was a complex mixture in -which 2,3,3-trimethyl-l-pentene was the pro'ba"ble 
major componorvt. This partial identification ie made "by a comparison, of 
the physical properties of cut D-3 with those of the 2,3,3-trimethyl-l- 
pentene isolated from Shell Hot- Acid Polymer, (See next section.) Since 
only small quantities of these cuts (D-2 and D-3) were available, no ex- 
tensive investigation was made on them. 

Cut E was combined with tho residue from the preliminary fractiona- 
tions. The combined material (27 liters) was fractionated in Column 11, 
and yielded 3.8 liters of 3,>4-,li-trimothyl~2-p9ntene (cis and trans) ("b.p. 
112.0° to 112.6° C, n D 20 = 1.^235, d so > 0.739) and if .5 liters of 2,3,4- 
trimethyl-2-pentene Cb.p. 11.6.1° to 116.2° C, n D 20 = 1.4275, d 2 ° = 0.7428), 
These two compounds were identified "by comparison of their physical prop- 
erties with those of pure 3,4,4-trimethyl-2-penten© and 2,3,4-trimothyl- 
2-pentene. The pure compounds were obtained "by the distillation analysis 
of Shell Hot- Acid Polymer and "by dimethyl- zinc synthesis. Part of this 
sample of 3,4,4-trimethyl-2-pentene was oxidized to pinacolone. The en- 
tire sample of 2,3,4-trimethyl-2-pentene was hydrogenated to 2,3, 4- 
trimethylpentane ("b.p. 113.41° 0, n D 20 - 1.4038 to 1.4o4o). • 

An approximate analysis of the original diiso"butylene (gas-free 
"basis) was made "by examination of the distillation curve's. This mixture 
was found to contain: 

2,4,4-trimethyl-l-pentene 70.0 percent ("by volume) 

2,4,4-trimethyl-2-pentene 18.7 

3,4,4-triEtethyl-2»pentene 4.6' 

2,3,^-trimethyl-2-pentene 3.7 
2, 3, 4-trimethyl-l-pentene|_ 

2,3,3-trimethyl-l-pentenej 1.0 
Other ootene(s) 

Polar compounds 2.0 

investigation of Hot-Acid Polymer (Shall Oil Company) 

(Unfinished project)- 

The investigation of Hot-Acid Polymer was undertaken to isolate and 
purify some of the major constituents. The general method of operation 
was the same as that used in the investigation of diisohutylenes, "but for 
this work more efficient, higher-capacity stills (12, 13, 14, and 16) 
were available. 

A total of .1041 liters of crude polymer -was subjected to preliminary 
fractionation in five "batches. Corresponding cuts from the several 



NACA TIT. Hb . 12^7 ^7 

"batches were combined. In this way, the polymer was divided into five 
portions. The data on these fractionations are given in ta"ble 5. 

Cut A, which contained "butanol-2 was not further investigated. Like- 
wise, the residue has not "been studied. 

By refractionation of cut B, there were isolated the following mate- 
rials: 

Cut B-l - 1C3 liters, 2,U,l(-trimethyl-l-pentene, "b.p. 101.1° to 
101.3° c/755 mm Hg, n D 20 > l.toSt to 1.4086* 

Cut B-2 - 9,5 liters, a mixture of close-"boiling olefins, To .p. 
107.0° to 107.1° c/756 ma Hg, n D 20 = l.hlAk to 1.4146 

Cut B-3 - 8.0 liters, 2,3,3-trimethyl-l-pentene, "b.p. 108.0° to 
108.1° C/753. mm Hg, n D 2 ° = 1.4173 to 1.4175 

A considerable amount of material "between B-l and B-2 has not yet 
"been investigated. This intermediate contains 2,4,4~trimethyl-2-pentene, 
associated with at least two other compounds with "boiling points near 
105° C. 

Cut B-2 was ref ractionated . The presence of several compounds is 
indicated "by the distillation data. A sample of B-2 was hydrogenated . 
Analysis of the product showed the presence of ahout 30 percent 2,2,3- 
and TQ percent 2,3,4-trimethylpentanes. 

Cut B-3 was refract ionated for isolation of a sample suitable for 
physical-constants measurements. A sample of this material was oxidized 
to methyl t-amyl ketone ("b.p. 130.8° to 131.2° C, n D 20 ■ 1.4201), of 
which the 2,4-dtoitrephenylhydrozone melted at 111° to 112° C. Hydroge- 
nation of a sample yielded 2,3,3-trimethylpentane ("b.p. 114.5° C, 
np 20 = 1.U073). 

Purification "by refractionation of cut C gave 100 liters of purified 
3,4,4-trimethyl-2-pentene ("b.p. 111.7° to 111.9°C/751 mm Egj n D eo -. 1.4231 
to 1.4233). The "best sample from this fraction was used to determine 
the physical constants. The presence of cis and trans isomers, which 
were only partially separated "by the fractionation, causes the wide- "boil- 
ing range. It is thought that the sample reserved for physical-constants 
measurements contained more of the higher-"boiling (trans?) isomer than of 
the lower-"boiling compound. (Oxidation of this compound "by sodium dichro- 
mate produced pinacolone in 30 percent yield.) '" 



48 WACA TW Wo. 1247 

Redistillation of 120 liters of cut D gave 45 liters of 2,3,4- 
trimethyl-2~pentene (b.p. 116.0° c/754 mm Hg, n D 20 = 1.4271 to 1.4272), 

National Bureau of Standards, 

Washington, D. C, July 15, 1Q46 

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NACA TN No . 12U? ^9 



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50 NA.CA TN No. 12^7 

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March 1910, pp. 582-589. 

25. Bergstrom, F. ¥.: Sodium Amide. Organic Syntheses, vol. 20, 

C. F. H. Allen, ed., John Wiley & Sons, Inc. (New York, N. Y.) 
I9U0, pp. 85-91. 

26. Whitmore, Frank C, and Church, James M.: The isomers of "Diiso- 

"butylene." Ill - Determination of Their Structure. Jour. Am. Chem 
Soc, vol. 5k , no. 9, Sept. 1932, pp. 3710-371^. 

27. Locquin, R., and Sung, W.: "Pennone" ou Titramethyl-2-2-3-3- 

Pentanone-4. Comptes Rendus ; vol. 178, May 1924, p.. 1179* 

28. Locquin, R,, and Sung, W.: Sur la "pennone" ou tltramethyl-2-2-3-3- 

pentanone-4. Bulletin de la Societe Chemique de France, ser. h, 
vol. 35, April 1924, pp. 753-762. 

29. Whitmore, Frank C, Marker, R. E., and Plambeck, Louis, Jr.: Studies 

on Hexamethylethane and Related Compounds. Jour. Am. Chem. Soc, 
vol. 63, no. 6, June 19^1, pp. 1626-1630. 

30. Nef, J. U.: tJber die Alkylirung der Ketone. Justus LleMgs Annalen 

der Chemie, vol. 310, 1899, pp. 316-335* 

31. Moersch, George: Synthetic Aliphatic Hydrocarbons of Nine to Twelve 

Carbons. Pennsylvania State College, Ph.D. Thesis, 19^2. 

32. Heyd, Josef William: " A Study of Compounds Containing a Neo Carbon. 

Pennsylvania State College, Ph.D. Thesis, 1937. 

33* Yule, J. A. C, and Wilson, C. P., Jr.: Peroxides and Gum in Gasoline. 
Ind. Eng.. Chem., vol. 23, no. 11, Nov. 1931, pp. 125^-1259, 



HACA TN No. 12^7 51 

3^. Schurman, Iman, and Boord, Cecil E.: Syntheses In the Olefin Series 
V - Completing the Survey of the Hoxenes and Including Certain 
Eeptenes and Octenes. Jour. Am. Chem. Soc, vol. 55, no. 12, Dec. 
1933, PP. >930-^935.- 

35 • Kistiakowslcy, G. B., Ruhoff, John R», Smith, Hilton A., and Yaughan,- 
W. E.: Heats of Organic Reactions. Ill - Hydrogenation of Some 
Higher Olefins. Jour. Am. Chem. Soc., vol. 58, Jan. 1936, pp. 137- 

36", TongTsergj, CO., Pickens, J. B., Fenske, M. E., and Whitmore, Frank C: 
The Isomers of "Diisolmtylene ." H. Jour. Am. Chem. Soc, vol. 5k, 
no. 9, Sept. 1932, pp. 3706-3710. 

37' KuyScendall, Sidney Benson: Syntheses in the Octene Series^ Octenes of 
Type III... Ohio State Univ., Ph.D. Thesis, 1935. 



NACA TN No. 1247 



52 



TABLE 1.-' DISTILLATION COEtMfS 



Still 


Type 


Sice 
(on) 


Paeking 


Pot capacity 
(«1) 


■ 1 


Total reflux, 

intermittent 

take-off 


6oo toy h.o 


3/l6-inch pyrex helloes 


5000 


2 




(see text) 




5000 


3 


Total reflux, 
variable take-off 


. 150 toy 2.0 


3/l6- inch glass helices 


200 to 5OOO 


h 


i 


150 toy 2.0 


3/32- inch stainless- steel hel- 
ices from 0.010-lnoh wire 


Do. 


5 


do 


150 toy 2.2 




Ho. 


6 


do—- 


150 1>T 2.2 


3/l6-inch glass helices 


. Do. 


7 


do 


125 toy 2.2 




Do. 


8 


do 


70 toy 1.1 


l/l6- inoh niohrcae helloes from 
0.010-lnoh vlre 


Do. 
Do. 


9 




1*0 toy 1.0 


3/6fc-inch stainless-steel hel- 
ices from 0. 006"5-lnch vire 


250 


10 


do 


2*3 tj-5.1 


Sash oheln 


U0,000 


11 




600 toy 5.1 


90 centimeter l/2-lnch cartoon 
rasohig rings, then 510 centi- 
meter 3/32-inch stainless- 
steel helices from 0.010-inch 
vlre 


75,000 


18 ft 13 


do 


1600 toy 10 .2 


3/8-inch porcelain rasohig rings 


227,000 


1* 


do 


1600 toy 5-1 


50 centimeter 3/8-lnoh porcelain 
rasohig rings, followed toy 1550 
centimeter 3/32-lnoh stainless- 
steel helloes from .010 Inch 
vlre 


227,000 


16 


do 


1600 toy 2.7 




113,000 


17 


Podtoielniak 
E^"p©rcal 


127 toy 0.8 


Hell-grid 


250 to 5000 


18 


do 


127, toy 2.5 




250 to 5000 


19 ft 20 


do 


250 toy 2.5 




250 to 5000 


21 


Dephlegmator 
controlled take- 
off 


120 toy 3.5 


3/l6-lnoh glass helices 


22,000 


22 to 25 


Total reflux, 
varlatole take-off 


183 toy 2.5 


3/32-inch stainless-steel hel- 
loes from 0.010-lnoh wire 


500 to 5000 


25 to 27 

.... 




I83 toy 2.5 


3/l6- inch glass helices 


500 to 5000 J 



NATIONAL ADVISORY 
COMMITTEE FOR AERONAUTICS 



53 



NACA TN No. 1247 



TABLE 2 .- PHYSICAL PROPERTIES OF OOKPOUND PREPARED 
[Values are believed to be precise to witbln a few units In the last place given 3 





FreMin* 
point 


Bo lline 
point 


ItB/oT 
at 760 cm Bf 


at: 

20-800 


Dm 


iltv 


JD/it 
20-25°C 


RefractiTi 


indax, Hq 


dn/dt 
20.25'C 


Data 

firat 


st 2O°0 


at 25»0 


at 20°0 


at 2J»0 


Compound 


In air 


at 760 ■■ He 


















preparation 




foj 


(•0; 


(•0/™ Eg) 


(•0) 


Ce/»i} 


f&M) 


(e/mi/'o) 






(np/oo) 


oonpletad 


n-Pentano 


-129.75 


36.075 


0.03 88 


0.006 


0.62619 


0.62133 


-O.OOO97 


1.35746 


1.35480 


-O.OOO53 


January 1541 


2-iit thyloutajoe 


-159.9 

-16.60 

-153.73 


27.853 


0.0386 


0.006 


0.61963 


0.61455 


-0.00102 


1.35357 


I.35067 


-0.00058 


Dacanber 1939 


2, 2-DlMethylprcpano 
fe-Kethylpentwie 


i'& 


i O.O361 ' 
0.0418 


0.017 
0.O02 


0.65285 
0.66438 


0.64S48 


-0.00088 


1.37141 


l.Vseif 


-0.00055 
-O.OOO54 


April 1942 
January 1944 


3-Hethylpentane 


a nf 


63.265 


. 0.0426 


O.OO5 
0.004 


0.65972 
0.64422 


-0.00093 


1.37646 


1.37376 
1.36585 


BbTaabar 1940 


2, 2-Biaethyrbbtuie 


*> -IOO.06 


49.733 


° O.04O7 


0.64923 


-0.00100 


1.36873 


-0.0O05S 
-0.00049 


Kay 194l 


2,3-JJinethylpflntana 
2,4-Dioethylpontone 


nf 


89.787 


0.0450 


0.002 


O.69510 
0.67315 


0.69090 
0.66579 


-0.00084 


1.39193 
1.38165 
1.40403 


1.38950 


illfOMt 194l 


-119.86 GO. 50S 

-m.git(np) 115.653 


0.0431 


0.003 
0.004 


-0.00087 


1.37903 
1.40173 


-0.00053 
-0.00046 


Kay 1941 


S-Hethyl-3-ethyipefitQna 


0.0477 


0.71931 


0.71523 


-0.00082 


January 1941 
aucuit 1941 


<£, 2,3-5?rinethylpentane 


c -112.32 


109. 847 
114.767 


0.0487 


0.002 


0.716OS 


0.71201 


-0.00081 


1.40280 


1.40052 


-O.OOO 46 


£ i 3 i3-*rimothylpontai:8 
2, 2, VSrimethylhexaiu 


-101.6 


0.0491 


0.004 


0.72621 


0.72229 


-O.0O079 


1.40757 


1.40521 


-O.0O047 


Ootober 1940 


-123. 4XH?) 126.54 


0.0503 
0.0485" 


0.011 


0.71555 


0.71178 


-O.OOO76 


1.40328 


1.40095 
1.39724 
1.46365 

1.41014 


-O.OO047 


Ootobor 1942 


2, 2, 5-f rimathylhoxac« 


-105.89(HF) 124.092 


0.005 


0.70711 


0.70313 


-0.00080 


1.39956 
1.40601 


-0.00047 


July 1941 


£i 3 1 5-Srinethylheuuu 


-127.9 


131.37 


0.0492 


0.021 


0.72191 


0.71792 


-0.00060 


-0.00047 


Juno 1941 


2, 2-Diaetbyl-3-ath3rlp«ntona 


-99.30 
-122.4 


133.834 


0.0506 


0.002 


0.73478 


0.73100 


-0.00076 


1.41227 


-O.OO043 


Saptaabar 194l 
Koreaber 1940 


^It-IUBethjrl^-BtiiylpQntano ■ 


136.717 
140,264 


0.0504 


0.009 


0.73793 
0.75676 


0.73415 


-0.00076 


1.41371 
8 1.42365 

1.41462 


I. 41146 


-0.00045 
-0.00044 


2» 2. 3 ,3-Ictr»n8tbylp«ntaDO 
2, 2,3 , 4-Ietraratthylpcntane 


-10.04 


0.0512 


0.009 


0.75300 


-0.00075 


c 1.42146 


Juna 194l 


-122.2 


133. 010 

141.544 


0.0501 


0.007 


0.73915 
0.754S9 
O.76450 
0.73542 


0.73537 


-O.OOO76 


1.41242 


-0.00044 


July 1941 


2>3 13 » ^•Istroaethsrlpcnbone 


-102.11) 


0.0514 


0.002 


0.75112 
O.76OSO 


-0.00075 
-O.OOO74 


1.42222 


1.42005 
1.42606 


-O.00O43 


Boraator 1941 


2 ( 2,3 ,3-IetrMothylhe sane 
2,«i,U t 5-Tetr««tth7lh£iBi:» 


-5^.03 


160.310 


0.053 s 


0.005 


1.42812 


-0.00041 


loraabtr 1945 
October 1945 
Aucuit 194; 

lueait 1945 
Karch 1945 


nf 


147.875 


0.0512 


0.011 


0.73165 


-0.00075 


1.41321 


1.41093 


-0.0004S 


2» 2» 5 » 5-IetrcjoetIiylhe sane 
3 »3 1 % 4-Tatranathylhcxana 
2,VWMthyl-3-i»oproprlpentaae 


-12.611 


137.457 
170.0 


O.050O 
0.046 


0.004 
0.57 


0.71875 
0.7824 


0.71430 
0.7789 


-0.00079 
-0.0007 


1.40550 

1.4368 


1.40J15 
I.434S 


-0.00047 

-0.0004 


-■}6% 


157.042 


0.0544 


0.012 


0.75826 


0.75460 


-0.00073 


1.42455 


1,42246 


-0.00044 


2> 2,3 • 3 1 ^-Pantanethylpentane 
2, 2,3 , % ^antnaftthjrlpentan* 


166.05 


0.0552 


0.039 


0.7SOO9 


0.77675 
0.76362 


-O.OOO67 


1.43606 


1.43412 


-0.00039 

-0.00040 


Tabruary 1942 
Octobor 19&4 


-38.81 


159.29 


0.0537 


0.052 


0:76702 


-O.OOO68 


1.43069 


1.42668 


3-Kethyl-2-pwitene (1,3.1.) 


-135.4 


67.8 . 


0.039 


0.16 


0.6942 


0.6898 
0.6942 
0.67312 


-0.000SS 


1.4016 


1.3989 
1.4010 


-0.00054 


Septanber 1942 


3-*Uthyl-2-pent«ne (E,B.I.) 


-138.5 


70.5, 


0.037 

0.0429 


0.17 


0.6986 


-o.oooss 


1.4045 
1.39044 


-0.00054 


Septauber 1942 
Ttfbruary 1944 


2, 3-Dlw thyl-1-lmt enc 


nf 


55.6UL 


0.002 


0.67792 


-0.00096 


1.38745 


-0,00060 


2, 3-J)i methyl- 2-biittne 


-74.3O 


73.206 


0.0424 


0.006 


0.70795 


O.70336 


-0.00092 


1.41221 


1.40944 


-0.00055 
-0.00047 


Ootobar 1943 


2 P 3 .3-lricfithyl-l»-p intone 

2,^,U-IM.m«th7l-lp-p«nten» 


nf 


108.4 


0.05 

0.0459 


0.27 


0.7352 


0.7308 


-o.oooss 


1.4174 


1.4151 


April ]'|45 


-93.56 


101.437 


0.003 


0.71500 


0.71076 


-0.00085 


1.40856 


l,4o6oi 


-0.00051 
-0.00047 


Juna 1943 


2,3 f l4-Trimethyl-2-peJit«i* 
2,4, lj-Trlnathyl-S-penteno 


-113.38 
-IO6.5I 


116.26 


0.0493 


0.082 


0.74342 


0.73914 


-0.00086 


1.42736 
1.41602 


1.42500 


July M42 


104.914 


0.0470 


0.007 


0.72124 


0.71700 


-0.00085 


1.41350 


-0.00050 


July 1943 


3,U t li-Trinctbyl-2-pentan« (OT) 


nf 


112.3 

73 (100 EH 


0.05 


0.42 


0.7392 


0.7350 


-O.00O S3 


1.4235 


1.4210 


-0.00050 


July 194i 


2,3 1 5-Trinttbyl-2-bcaene 




> 




„ „_ 







1.4299 






Ootobor 1940 






58 (50 an) 




















2*3 »3 > tMEetraovtbyl-l-peataQe 
4-&etbyl-3-lfloprop7l-2-p«iitei» 




133.2 


0.051 

0.046 


0.30 


0.7587 

0.7627 


O.7549 


-O.OOO76 


1.4306 


1.4283 


-0.0004S 


Korocb.r 19)41 


nf 


138.0 


0.88 


0.7591 


-O.0O072 


1.4353 


1.4328 


-0.00049 


luguit 1940 






96 (200 m 


) 


















J^VWnrthyl^etliyl-a-penteae 


-S3.5 


129.97 

88 (200 iz 
134.03 


0.0459 


0.073 


0.74392 


0.73997 


-0.00079 


1.4234S 


1,42112 


-0.00047 


iucuat 1943 


U a t)-Dimethyi-3-ebh/l-2-pGntene (CT 


1 nf 


0.0466 


O.06O 


0.7561 


0.7521 


-O.OOO79 


1.4309 


1.4285 


-0.00049 


lueuat 1941 






84 (150 ra 


) 


















3 ,3-^>iiiethyl-2-i sopropyl-Mntt eno 


-78.2 


122.21 


0.0502 
0.049 


0.037 


0.73614 

0.7448 


0.73228 
0.7407 


-0.00077 


1.41669 


1.41431 


-0.0004S 


Ootobor 1941 


2,3,5, JJ-Tetranebbyl-l-hexeiie 


nf 


142.8 


0.185 


-0.00082 


1.4226 


1.4203 


-0.00046 


July 1945 


'2 l 3 t 5 t 5~Ietreaothyl-2-hexftn« 


nf 


156.2 


0.049 


0.34 


0.7659 


0.7622 


-O.OOO74 


1.4374 


1.4351 


-0.00048 


July 1945 


2»2»5,5-I«tron»tiiyl-3-hexeiie (01) 

2»3.3»% 1 ^-Pentwiiethyl-l-pentene 

2,lt-Dinetbyl-3-lflopropyl^-£-pont«n« 


-4.75 
+38.66 


125.013 


0.04SO 


0.010 


0.71673 


0.71223 


-O.OO09O 


1.4n48 


1.40890 


-0.00052 


July 1945 


158.75 
152.4 


0.054 


0.039 
0.34 














Soptaotor 1944 
Tabruary 1945 


-55.3 


0.051 


0.76SO 


0.7637 
0.7671 


-0.00084 


1.4377 


1.4353 


-0.00047 


3,3-IHn»tlvl-3-t-batyl-l- , batene 


-62.9 


150.3 


0.052 


0.22 


0.7710 


-O.OO077 


1.4359 


1.4339 


-0.000 4o 


April 1944 


2,3-DlorthyI-l,3-tutft41»E* 




68.5-71.5 






0.7267 






L.4366 







Kay 1940 


3-Kethyl-3-p«ntaJiol 


-23.6 


122.4 

80 (150 DD 
116.4 


0.039 


0.30 


0.8286 


0.8243 


-O.OOO86 


1.4186 


1.4163 


-0.00046 


iutuat 1941 


2 ,3 -SlDethyX-2-^butaul 


-1D.4 


0.037 


0.042 


0.8236 


0.8193 


-0.00086 


1.4170 


1.4i4s 


-0.00044 


Oetobir 1943 






76 (150 m 


) 


















3,5,5-2rinethyl-3-heianol 

2 f U-Din»thyI-3-«thyl-3-paiitaJBl 





71 (25 «■] 







0.S35O 








1.4352 
1.4439 






July 1941 


-16.O 


96 150 ns! 


0.048 


0.70 


0.8588 


0.8543 


-0.00089 


1.4416 


-0.00045 


July 1940 


2, 2^Din*thyl-3-*rthyl-3-peatanol 


-19.0 


174 

94 (50 m) 
173. 4 

94 (50 m) 
194.5 

109 (50 nun) 
194.4 


0.05 


1.55 


0.8572 


0.8526 


-0.00091 


1.4429 


1.4405 


-0.00047 


July 1941 


2,2,3, 4-Tetrnnethyl-3-poataiiol 


+12.8 


0.047 


0.83 


0.8565 


O.S523 


-0.00065 


1.4405 


1.4428 


-0.00047 


July 1941 


2, 1 t-Wcatliyl-'5-i60prop7l-3-pdntBiio 


-14.7 


0.051 


0.77 


0.8632 


O.8591* 


-O.OOO 83 


1.4430 


I.445S 


-0.00043 


Deoonbor 1944 


2, 2,3 « **» M-Pentanethyl-3-pentoool 


+42.1 


0.059 


O.JS 














Tabruary 1944 


2, 2, U-fricethyl-3-pectanono 


-29.02 


136.190 


0.0485 


0.007 


0.S0654 


0.80229 


-0.00085 


1.40596 


1.40389 


-0.00042 


Juna 1941 


2, 2, 4, l f-Ietr£uaethyl-3-p*ntonone 


-25.24 


153.521 


0.0521 


0.010 


0.82409 


0.82027 


-O.OOO76 


1.41927 


1.41712 


-0.00043 


January 1944 


Ethyl Brine thyl acetate 


-89.55 


118.35 


0.0453 


0.061 


0.85467 


0.84952 


-0.00103 


1.39061 


1.3E82L 


-0.0X48 


Juna 1941 


3-Chloro-2, 2,3-Erinethylpentane 


-17.9 


87 (62 en) 







0.9066 







1.4441 








July 1942 


2-Chloro-2,3 ,3-5rL*aetliylp«ntQiie 
3-0hloro-2, 3 , q-Tridftthylpentanel 
3-Ohloro-2, 3 , 4-IrinatlylpentaneJ 


+10.6 


82 (57 ran) 
82.86 (60 






0.9105 


O.9065 


-0.00080 


1.4457 


1.4436 


-0.00042 


Juna ISU5 


-_- 


on) 




0.888 








1.43S 




. 


Auc»t 1942 
























l-Ohloro-2,3-I>lnotbyl-2-buteno 


— 


32 (45 an) 




— - 




















Kay 1940 



a Syoibole: nf, material became very riscoue or glaney without freezing 
to a oryetailine aolid: nd r material considered too inpure to Tarrant 
determination of freezing point j UP, melting point; L.B.I. , lover-boiling 
^eouetrio isomer) H.B.I. , hi£aer-bolling geometric ieomerj OT, aixture 
of geometrio isomers. 

D Bee referenoe 5. 

See referenoe 4. 

^ Oaloulated fro.x data given in referenoe 13. 

e The rofraotive indicoe of 2,2,3,3-tetramethylpentane wore determiaed 
bv Ur. Leroy Tilton on the Optioal Instruments Section of thiB Bureau. 



NATIONAL ADVISORY 
COMMITTEE FOR AERONAUTICS 



TABLE 3.- mrraoCAKBOHS ISOUBBBD IfiOM "BOTEKE AEErLKEE" 



Hydrocarbon 


Boiling 
point at 
760 an Hg 
(°C, Cottrell) 


Befractive 
index, n^ 20 


Volume 
isolated 

NO 


Toltmo (percent) 
of total 
Butane 
Alkylate 1 


Isopentane 

2,3-DirothyIbutane 

2-Methylpentane 

3 *Methylpentane 

2,4-DImBtbylpentane 

2, 3-Dtottethylpentane 

2,2,4-Tria»thylpentane 


27.9 
57.9 
60.2 

63-2 
8O.5 
89.9 

99.3 


1.3531 to 1.3533 
1.37*9 to 1.3752 
1.3714 to I.3716 
I.3761 to I.3763 
1.3815 to 1.3820 
1.3912 to 1.3920 
1.3912 to 1.3915 


728 
2,213 

224 

224 

2,6lD 

1,034 

11,727 


0.97 

2.97 

.30 

•30 

3.44 

1.37 
15.48 



> 

SI 
o 



-3 



3 The data in this coluux represent the amount isolated having the properties 
shown. It does not constitute an exact analysis of the crude. 



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TABES k.- TXmSZOB OF BUSOBOTILEtTE BY PSEUMUfART FRACTIOHATION 



CJl 
CXI 



Cttt 


Yolune 
(11 tars) 


Toltmo par- 
coat of total 


Boiling range 1 
(°C) 


Refractive index, 


Major constituents 


A 


Ik 


3-1 


Below 101.? 


1.392 to l.*082 


2,^,^-Vrinethyl-l-pentene, 
butyl alcohol, other polar 
conpounds 


B 


26k 


57.8 


101.5 to 102 


1.1»0& to IJ1O88 


2,^U-TrlMethyl-l-pentene 


c 


58 

■ 


12.6 


102 to 10* 


l.Ii09^ to 1.JH27 


Xateraedlate, ndxtnre of 
2,U,lf-trl»etlijl-l- and 2- 
pentenes 


D 


95 • 


18.7 


IX* to 107 


1.M50 to 1.M60 


2,^,lHTrlmeta7l-2-pentene, 
end snail quantities of 2,3,1*- 
and 2,3,3-trlioethyl-l- 
pentanes, and other ootenes 


B 


27 
(Includes 
residue) 


6.0 

(Includes 
residue) 


107 to 117 


1A207 to I.U238 


2,3,^-TrlMethyl- and 3,M~ 
trimethyl-2-pentenee 


Goa and 




1.8 








loss 













^Cottrell boiling-point Measurements on first and last fractions* 



o 
> 

52! 
o 



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}->■ 
CO 









ID PGLTKER BY HTKT.TMTWAHT HRACTTOIATION 


f 


TABLE 5.- JJH 


jsxm of wn ac 


> 


Cut 


7olu» 
(liters) 


ToItbw per- 
cent of total 


Boiling range 1 


Bofractlve Index. 


Beaarke 




m 


A 


38 


3.7 


<101 


<l.i»o8 


Forerun 




B 


200 


24.9 


101.0 to 101.7 


i.to8 to 1.1*20 


2,U,1*-Trinethyl- 

1-pentene 

2,3, 1 HTrln8thyl- 

1-pentene 

2,3,3-TrlH»thyl- 

1-pentene 




C . 


2k6 


23.6* 


U0.1 to 112.0 


1.1*21 to l.fc23 


3 , U, 4-TrlM»thyl- 
2-pentene 




D 


I69, 


16.2 


113.0 to 116.0 


I.U25 to I.U26 


2,3,^-TrijBethyl- 
2-pentene 




T 


5f)8 


90 


>ll6 




Residue 




Gas and 
Iosb 2 




11.6" 







^Jotfcrell liolling-point Measurements on first and last fractions. 

2 A preliminary distillation of 2 liters Indicated over 10 percent gas. 



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COMMITTEE FOB AERONAUTICS 



CJl 

en 



24.31r 



E4.30 



84.39 



24.28- 



I 



S24.27- 

3 
-p 
a 
■H 

ID 

■1 

a 



34.36- 



24.36- 



24-241- 



ai.aih 



,.-34.3653 OhmB-O--li3.638 o 



O Q ' ► o ° O i ► O 



a 9 o > o o 



o a < i o 



° o 6 rt 



0.1 U 



o o ' o o 



° O li O n O 



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COMMITTEE FOft AERONAUTICS 



20 



30 



50 



40 

Time, min 
riguro 1.- rraoelng point of 2,3,5,5-totruiatbylbexaae. 



60 



E 



■-3 



SB 
O 



I- 1 



3 



NAOA TN No. 1247 



Fig. 2 



135. 58r 



135.51 



135.50 



135.49 





2,3,5, 


5-T etramethylhexane 




P «= 760.90 urn 


hg 




















i 
















° 


r ° 


o 






: i 


o c 


o 9 o ^ o 










o 




















o 





















so 



40 60 

Recovery, percent 



80 



100 



125.83 



125.81 



125.80 



125.79 





2,3,4- 


Crlmethj 


laex&ne 






P ■ 745.91 mm 


ug 












\ ° 




o 


1 




< 


, » ' 


o- ' 


O 












o°^ 


o 



















e 

u 

o 



£l25.10r 






125.00 



124.90 



124.80, 



20 



40 60 

Recovery, percent 



80 



20 



40 60 

Reoovery, percent 



80 



100 





2,3,5, 


5-T et ran 


ethyl-3- 


hexeno 




P - 74 


'.11 mm 


Ig 












< 


o 


o 


o 

( 

1 


o 

1 


1 


O O ( 




O 

c 


o 

i 


o 
















100 



101.54 



101.53 



101.52 



101.51 





2,4,4- 


trimetny 


l-l-pen1 


ens 




P - 7t 


il.81 mm 


bg 






o < 


1 O ( 


I o < 


o 


< 




o 


O < 


■ 


o o o <! 
o 






' 















20 



80 



40 60 

Recovery, percent 
Figure 2.- Boiling point of four representative hydrocarbons. 



100 



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■4 



£ 

4 



FlguiB 3.- 



ao 

Tims, or 
R»t OB at peroxide formation la 2,3-dlraethyl-3-butene 
and 3,3-dimetliyl-l-lJutena. 



10 80 30 40 50 

figure 4.- Bata of peroxide formation in 2,S-dimethyl-l-butene. 



04 



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